I just got my yba 200 delivered yesterday. I came home from work and found that UPS had left it on top of garbage can behind my house while it was raining (rather than on the enclosed porch or out front or covered covered patio out back right next to the garbage can). The box was falling apart from the rain but the amp was fine. I haven't has a chance to gig it yet, but from the hours I played with it today, I'm pretty pleased.
This is one of the new versions without self-biasing and it came with KT88 tubes. I hooked it up to my trace elliot 1x15 and fender 4x10 and was impressed in both cases. I've read a lot of complaints about the preamp being too bright, but I was able to get a lot of different tones from my passive jazz bass. I'm accustomed to a passive tone stack on both old fender tube amps and my Sovtek head, though.