These IEMs are not jack of all trades, which means they do not perform like their main rivals in the price range (300-500 dollars).
 
Most IEMs in this price range, such as UEs, shures or Westones use multiple balance armatures to produce a relatively good sound through all range, the GR10, on the other hand, uses single armature, there is a inherit disadvantage of this design, as one single armature cannot cover the whole range as good as the multiple ones. In the light of this, the GR10 lacks treble and bass energy and extension which most of it's rivals possess. I did not mean the treble and bass quality aren't good, both of them are well controlled and of high quality. The less treble and bass energy makes the IEM non- fatiguing.
 
Above is the "weakness" of these IEMs. But their strength is so strong, that make me overlook it's weakness. In fact, the GR10 is one of my favourite IEMs.
The GR10 has a woderful wonderful mids, the mids is a bit forward than it should be, makes it's sound quite engaging, and the quality of it's mid is superb, even surpass most $1000+ universial IEMs such as IE800, K3003 and SE846. On top of that, it's sound has great instrument seperation. The soundstage is quite big for an IEM also. As a single balance armature design, it's sound has a beautiful coherence. 
 
The IEMs looks nice and small, the comfort is quite good on par with IE8, there are some customers complain about hard to get the right seal, I do see the ear tips a little bit strggle to get the perfect seal for some, but in my case it is alright.
 
In conclusion, the GR10 is an adorable IEMs which has maybe one of the best midrange in the market, it's engaging while non-fatiguing, it probable be one the best headphones/IEMs for vocal and pop music. It is also pretty good for many other genres. The GR10, to me, is one strong contender in the mid-price IEM market and well worth your consideration.

The review will comming soon

The RS1i, along with other Grados, have the reputation of being difficult to pair with. I own/owned 8 pairs of Grados, and auditioned the whole Grado product line, I would say the RA1 & RS1i combo are, by far, the most satisfying and musical pairing.
 
Many Nay-Sayers bashing the amp for generally two reasons: 1, the company use some cheap components to build the amp; 2, the amp has relatively inferior sound quality in terms of clarity, speed, etc. True, the amp is not the most detailed/spacious sounding amp in the market, even not quite as good as it's rivals in it's price range, but I think it fulfill the most crucial part of this hobby, the pleasure of listening to the music.
 
Paired with most other systems, the Grado headphones share similar sound signatures: boosted treble and bass (some lower priced models don't have bass boost). Most Grados model can be fatiguing if paired with wrong system. I've tried the RS1i with many amps that cost several times more than the RA1, but the sound were either too bright, or the overly punchy bass make my ear hurt after long term listening. The RS1i can actually sound pretty impressive with some of these amps, but none of the pairing makes me very engaged for there always some part of the sound distract me from enjoying the music. At times, I was disappointed by John's tuning and even go so far as, thinking his vision of sound is too aggressive and too focused on particular genre.
 
But I still didn't give up hope on the Grados as they sound vivid compared to aother manufactures in the industry. I recently read an article on touring the Grado company saids that Grado tunes his phones in his own system, and the RS1/RA1 combo should reflect his true vision of sound. My faith in him finally paid off. Paired with RA1, the RS1i sound open, clear and smooth, there isn't noticeable boost throughout frequency, the overall sound is quite neutral yet not "boring", everything sound vivid and natural, nothing distracts me from enjoying the music. There are certainly trade-offs for being smooth, it sacrifice a bit of details of the sound, but I believe increase of the smoothness worth the loss of details as it is better for long term listening. The sound quality may not as impressive as some other pairings, but the the combo sounds very satisfying. The tonal balance reminds of the MS-pro, just smoother. The smoothness of the sound also make me related the combo with the HF2 and PS500. I guess Mr Grado tuned these two models this way as he's noticed that not many people using his amp with his headphones .
 
As we enter this hobby longer, we've develop more sensitive hearing that helps us to judge which sound are well-tuned whereas which are not. The sound  of RS1i and RA1 combo is definitely a sophisticated and engaging one to me. If you are after musical pleasure, the combo will not disappoint you.
 
To relate the two component with the topic, the RS1i is the bacon, it's nice but salty, the RA1 is the egg and it's plain, they taste alright by themselves, but if you put them together, they just work wonders.
 
Edit:
The combo will sound best with warm sounding DAC and cables.

Actually I bought this headphones just for it's box.
 
Anyways, they‘re of great value,for the price you'll get clear sound and tons of details when paired wit bowls (although not in good quality compared to more pricey models). They are outstanding rock headphones, especially in it's price range.
 
But like most Grados, they are quite bright and can be fatiguing.

I own these canalphones twice. I lost my first pair two years ago and I miss their sound so much so I bought another pair.
 
The sound of these IEMs is very neutral and accurate yet without being analytical, the tonal balance is almost perfect.
 
They are excellent for rock and classical music, but may not as engaging as some other models for Pop and R&B.
 
In conclusion, they are one of my favorite IEMs. It is very impressive that after over two decades in the market, they still can hold their own ground against to some more pricey and newer models.

Back in year 2008, when I saw the picture of rs1(buttoned) on a website for the first time, I said to myself “darn these cans are expensive, I wish I could have mine one day". A few years later, I finally hold these baby in my hands. The build quality of these cans are as bad as I expected since I have already owned several grados. But what I care about is the sound quality, and its just BEAUTIFUL!
 
I love the treble sparkle and intimate sound of my sr325is, but they are too bright for some genres and could be hurtful to my ears in long term listening. I also love the bass texture of  my mspro, but they are a bit too tame in high frequency so that they don't have the "sparkle" for rock and metal misic. The RS1is have all the advantages that 325s & pros have: treble sparkle, mid and low frequency texture, punchy bass and intimate grado sound.
 
Although they are not cheap, and the build quality couldn't be any worse for the price, but for the musical delight they bring, those shortcomings don't seem that obvious. They are trully a classic.
 
 
Edit:
 
The tonal balance of the RS1i is not the best I've heard, I wish they could have a bit more treble  sparkle and less bass.

The sound of SR325is is on the bright side of neutral. They are one of the most exciting cans for rock and metal, they can also do jazz and pop pretty well.
For some music such as hip hop & RnB, however, the bright sound is just not suitable for these genre as they are overly bright. So personal preference and system pairing is essential.

Edited in October 2015:

After 3 weeks waiting, I finally recieved my third pair of mspro. I paid eye-watering 1200 AUD for this new old stock i version. FYI, the RRP of Byer T1 in Australia is AUD1050 and 1300 dollars for HD800. Am I crazy? After I state my opionon, You'll be the judge.

Why should I spend this much for this very model, and purchased three times? Because the mspro ticks all my requirement boxes. And the new e version has quite different sound, which I don't like.

The woodies have a near neutral tonal balance, just add a bit warmth to the sound. The bass of mspro is tight, fast and slightly punchy, although less punchy as most i version Grados but adequate for most of my music.

Mids is smooth and of awesome quality, the position of the mids is neither too forward nor too distant.

I mentioned in my pervious review that I thought the treble is the weakness of the mspro's sound a few years ago, as I am older and have more listening experence now, I began to prefer the 'shimmering' treble presentaion over the 'splashy' treble of most i version Grados. For example, AC/DC's Back in Black, symbals and snare drums are more straightforward and with less decay on most Grados while the mspro's is more delicate and with longer decay. Why I've change my preference? When I was younger I prefered more exciting presentation, simply put, I was a treble-head, but the 'splashy' treble of most Grados makes me fatigue after a while and became more and more painful, so I end up selling most of those cans. The Mspro, while maintain that clear and open sound, it's 'shimmering' treble is less hurtful to my ears, which is more suitable for longer listening sessions.

The soundstage of the mspro not huge but very accurate and round. Enough for rock, jazz and midium scale symphany.

Comfort wise, as I don't like muffle fit of most over-ear headphones, the on-ear mspro makes a good companion in warm weather.

The purchase of the mspro this time for the price is a 'heart over head' decision, but for a discontinued model, and a model I really want, I kind of feel lucky that I could still snatched a new stock.