Between a Mesa triple, dual, and single rectifiers? I love the triple. Don't have the cash for the triple, don't need 150 watts, don't need three channels, will I be alright with the single?
Probably one of the biggest things is the headroom offered by the high wattage. I've messed around with a single recto (which has no reverb, by the way, unless you go for the rectoverb) which is 50 watts. I didn't really get a chance to really test it at high volume but I'd imagine you'd notice tonal differences between a triple and single when you're really pushing the power tubes. They're all rectifiers, but you may also want to look into the dual roadster, which is pushing the price around the triple solo head range.
Yes, there is. It's not a very large difference though (they still sound very similar). The Singles have SS rectifiers and are the tightest. The Triple is the most loose of the three and the Dual is somewhere in between.