Pros: detail, clarity, strong (but not overpowering) bass, good at pretty much all genres
Cons: not so comfortable, looks are hit or miss, feels plasticky
Let me just start by saying: i'm no audiophile. These are my first pair of full size headphones, and i am certainly not disappointed. So on to the review:
not good. I tried a pair at a headphone store; at first, their soundstage was obviously thin, and the built quality itself left a little to desire. It was also rather uncomfortable than and did not seem to offer much of an upgrade from my Shure E2cs. Despite this, i was convinced (in no small part by the staff) that these were the best i could get for my money, and that i would soon grow to love them. After listening to these for nearly two weeks, i have to agree.
Funnily enough, they sounded much better than the pair in the store. The sound did rather smooth out after burning in, but i cannot say if that is due to me getting used their sound signature, or they actually got better due to burning in. I can barely stand to listen to my old IEMs because these just sound SO MUCH more clearer. I had no difficulty with the soundstage; it's not great, but it doesn't hinder the music in any way. In fact, i would argue that soundstage is more dependant on the recording and mastering process (once again, i'm no audiophile so i have no clue). The bass is strong, but does not overpower the music. It's not so "in your face", e.g. in the track "Limit To Your Love" by James Blake, the bass drop is not so head shudderingly strong, but the background bass is very evident. The highs are, admittedly, on the strong side but just like the bass, is not so overpowering.
I've listened to pretty much most genres of music with these headphones, and would conclude that these headphones can handle all genres well (except classical, which sounded rather dull, but still good). That being said, it does tend to favour "forward" sounding genres (the new Neon Indian album sounded great on these)
Now on to the design. Personally, i LOVE the retro look of these cans, but some people may not enjoy the look. One downside to the MS1i revision is that these now stick out a bit more. I wouldn't suggest using these out in public however due to the issue of noise isolation and leakage.
Obviously, these do not isolate at all, and leak quite a lot to boot. These are intended for home use, which is also reflected in their plasticky build. If you just use them at home, i can see no issue, but as soon as you take these out, you can understand why these give such great sound quality for the price. Alessandro (or Grado to be more precise) have designed these to give the most sound quality for the price, which has consequences on build quality and noise isolation and leakage. But you would probably already know this, having read other reviews.
Now on to, in my opinion, the MS1is greatest weakness: comfort. Although these have certainly become more comfortable since the first time i put them on my head, they are still not what i would call comfortable. That's not to say they are terribly uncomfortable, but nor are they comfortable for long usages. Firstly, the pads heat up rather quickly especially if it's a hot day. Secondly, the pads are rather scratchy, and prefer to push your ears down than conform to their shape. Some people do find Grado cans comfortable, but not I.
Update: Actually, these get MUCH more comfortable after break in. I can now wear these for hours (but still have to take short breaks each hour due to heat). Overral still not great but decent nonetheless.
I know that i talked about its downsides longer than its upsides; don't get me wrong, these are great cans for the price. Soundwise, i can only describe it as fantastic. It just has a few minor flaws which make it slightly less enjoyable. Regardless, i'm still happy with my purchase; my ears are still crying with joy, even though they may be slightly hot and sore.