I was in EXACTLY the same dilemna you are. I bought a Hornat and ordered a Xin amp (supermicro).
Here was the decision point.
- It's immediately avaialble
- It fits into my gigabag (it's really pretty darned small)
- Of the reviews i've read, it appeared to consistently be liked better than anything that fit the first two points.
- RSA has Extraordinary customer service. (ray has responded to my inqueries within hours prior to the sale, and has a great reputation)
- It's readily re-saleable (transferable warranty)
- It can drive full size cans (Ray tells me it was designed to drive the HD600's, and also that UE and others use his amps to voice their headphones)
I traded off the tomahawk's small size and battery life also based on reviews that claim better sound quality (without auditioning them both, what else do we have to go on).
The Pico sounds great in concept but is not currently available. In that same list of great reviews or expectations but is not yet available (anything Xin, iBasso D, Larocco PRII or Diablo).
So given all that Hornet made the most sense.
Now...i have it, it's been burning in for almost 3 weeks. When driving my UE11's, on the lowest gain setting, the volume is only set to about 2.5 out of a range to 10. So the ability to move the dial and make small incremental volume changes isn't there for me. Dunno if that would bother you, and i'm not even sure if it bothers me. Very frustrating that the only real way to figure this out is to have both, listen to both, and make the decision. Thank goodness for headfi meets (there's one local to me in two weeks where someone is bringing a tomahawk).
Good luck...
the more you read this forum, the more you'll realize that the advice on these things isn't authoritative, but opinion. Just extract things that appear to be verifiable facts (or at least trends), and use them to help decide for yourself. (maybe that's just obvious, but it seems many of us are looking for an answer to a really subjective question..)