My experience with IEMs are few. Check out Crinicle's review on what he said on this and skip the reading the remaining. Size is comfortable fit unlike those multiple drivers IEM. Coupled with the given foam tips, it can be worn for hours straight without feeling sore or fatigue. Upgraded to this from a sub $100 single dynamic driver IEM - Ar**. So is IE600 10 times better? Certainly not. For sure, IE600 is more pleasurable to listen to and this alone will justify the extra money spent IMO. In terms of details and technicality, IE 600 is on par with what a balanced armature can offer. Minus the BA timbre of course. At S$1099, it is pricey and is end game for yours truly.
Great sound as always. Different tuning that Sennheiser normally has, a more neutral sound but very wonderfully tuned.