I prefer tube. I remember before I used tubes, how I thought nothing could really be better than my SS. Then I got my tube amp... I couldn't really hear the difference at the time, but I loved the "feel". Then after playing that for a lot of clean & distortion for about 5 months, I was asked to come in to friend's band practice to help them write, not wanting to carry over all this crap, I just grabbed my SS amp. Plugged it all, and whoa!!!!! The clean made me cry. It was like ice-picks. I never realized it sounded like that.
I don't know how else to describe it, but I just don't like how "ice-picky" solid states are, or I guess you could say "pristine"... I like my clean tones to be very warm and smooth, and I've only been able to do that with tubes.
And wow... I feel like an idiot for asking this. What exactly do you mean by "breaking up" on clean? What does it sound like? Either I've never experienced, or I'm too dumb to hear it.