Indeed, there are 3 factors to consider : price, space and power consumption. And even if a full transistor preamp will sound way better than anything, all parameters will be on the far right indicator. That said, I've tried almost every onboard preamp and, to date, the best one and most transparent is the Richter BassXX which is a ... filter-based cleverly designed preamp with surface mount components.
http://www.richter-ee.de/preamps1.html