I believe for many people this is the most important factor re: impressions of the Arrow (and the main reason why this thread should be in the right place with portable amplification). Many people cannot afford several portable amps for their headphones and want to buy the one that is the best for their set-up. It has already been stated somewhere in one of these two threads that Robert uses HD650s while AverageJoe (at times at least) uses IEMs. The Arrow has come out shining on both ends of the spectrum and this is no small feat in itself. I personally have not heard a better all round, truly portable amp. Is it perfect for every HP/DAP combination? I doubt any amp is, but to my ears the Arrow is certainly the best you'll get for your money (and often more) with most portable set-ups.
I am not really very adept at describing intricate details of soundstage, resolution, warmth, clarity etc. It has been shown both here and elsewhere that these terms mean different things to different people (even if they do have an objective definition). As far as my understanding of these terms goes, the Arrow excels at them all.
When the Arrow has been compared to other amps (by either myself or others) it has usually been to amps costing $100 -> $200 more and it has come out as at least equal in most respects and better in some. IMO this makes the Arrow a no brainer for someone on a budget or anyone looking for real value and SQ. The money saved would be better spent on music! It has been hotly debated whether very low impedance IEMs even need external amplification. Only the person using them can decide this and it seems the Arrow is an inexpensive way to begin experimenting.
If anyone knows how to get this thread moved to the proper section, it would be a service to anyone looking for a great portable amp. It would also give the Arrow some of the exposure it deserves as one of the best (ultra) portable amplifiers.
Hellenback, I emailed Jude about moving the thread, but possibly, that wasn't the best way to get his attention. I'll try a PM.