When I had my rack rig I went through the following power amps over the years:
Randall RT2-50
Marshall 9100
Mesa 2:90
VHT 2/50/2
Peavey Classic 50/50
I was going for a Marshall type tone using a Randall RM4 preamp with all Vox or Marshall flavored modules, mostly modded. The hands down winner was the VHT with EL34s. Second place was the Peavey. The Mesa was the loudest which is no surprise since it had more power, but it was either too tight or too loose depending on how I set the various switches in the back. My least favorite was the Marshall which only sounded good completely cranked and even then had an upper midrange honk that I could not dial out. The Randall simply had no nuts and was the least punchy of the bunch. Cabinets I played through had Celestion V30s, Greenbacks and GT75s. They all responded differently to each amp obviously, but all of the cabs sounded great with the VHT. I got the Peavey as a backup when my VHT was fried by bad power at a venue and was shocked at how great it sounded too. Not as ballsy as the VHT but very similar mids and high end.