I've said it before and I'll probably say it again; Not only are Yamahas the most neutral amp I've come across, they're the only ones that never broke on me mid-gig. If you want color, the others all have some - try them & find the shade you like. If you want to hear exactly what comes out your pre-amp - or if you want to start every night knowing you'll end it using the same amp - get a Yamaha. I have more limited experience with the new ones, but they seem just as good, and they're all 2 rack spaces.
Peter (who has no connection to Yamaha other than the warm, relaxed feeling a rackfull of them gives a soundman)