Ok so I wen't on rampage recently and I've tried to raplace C10 with something that is more user friendly for every day use. I've bought Pioneer XDP-100r, Astell & Kern Ak300, and auditioned astell AK70, AK380, Questyle QP1r, Some time ago I've also bought and selled Plenue P1 also with the intention to replace C10.
This is how I feel about each of them:
Plenue P1 - a real let down. Boomy base and artificial treble. It sounded only little better then my old cowon s9. Don't know from where all the good reviews came in. Colorfly just destroyed it in every category in terms of sound.
Pioneer XDP-100r - absolutely great sounding DAP. Very balanced sound, maybe a little thin in the middle but nothing to complain about, forward sounding, never dry or harsh. Great clarity, resolution and best soundstage that I heard from a portable source. It completely lacks however. musicality. It's sounds great but somehow listening on it I'm not excited about the music and I'm not having a good time. Albums that i like bored me halfway through.
Qp1r - forward sounding, great bass, tons of power, horrible stering wheel that feels like it's broken. The thing that bothered me with it is that it sounded to slow. So slow that at first I thought that there was some option on with playback slowed down.
AK70 - good player but unfortunately not in the class of mentioned players here.
ak380 - very good sounding player but the price it's a joke.
ak300 - quite pleasant although it has a little recessed highs and with accent on base it sounds a little darkish. It has a very good resolution and the overall sound seems very refined. Darker signature with very good sound in technical way balances the overall experience and you can hear every detail even on low volume. Perfect player for long listening sessions. It's not as involving as c10 unfortunately.
Conclusion: I'm still sticking with C10. It's sounds so good that I can forgive it's poor ui.
FYI
I'm not a colorfly employee or anything. I just like this player so much