I have not played a CF guitar, harp or otherwise, so I can't comment on the sound, but I personally would need to play one first before buying one. Wood guitars, especially with spruce tops, are pretty safe bets, but CF is a totally different material, and videos are not going to tell you much about what a guitar will sound like in person. I'm obviously partial to Tonedevils, and am extremely happy with both of mine.
Plugged in, I can get awesome sound with two mics, and I've done some recordings with my S18 that sound professional, but the onboard pickups leave a lot to be desired in my opinion. They are not active (no battery), that might be part of the problem, and perhaps I really should use a pre-amp rather than plugging straight in to an amp or recorder, but I'll take a decent mic over the onboard pickups any day. Gigging, it probably doesn't matter so much, and your major concern will be taming howling feedback from that big top. There again, a mic may be a better option.