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.