There is something to be said for a "real tube amp". I was amazed the first time I played into one. I had walked into the store to buy a Line6 spider amp with built in sims and effects. I wasn't impressed. The sales person walked me over to a Peavey ValveKing and suggested I try it. The price was the same as the Line 6 amp. I was completely blown away. I walked out of the store with that amp.
Usually I use the crappy amps in the rehearsal studio, but last week I had to bring my amp. It was nice to bring it out for a spin...sounded soooo much better. It responds much better to my playing...it's the only way I can think to describe it.
The amp sims give you an approximation of it, but there is no substitute for the real thing.