Map,
There are a lot of combinations and permutations here, so in brief.
1) 100s run full range w/ss amps
I tried the Bel Canto (switching amp) and the TAD monoblocs (traditional class AB). Both worked well. The auditions were too brief for any definitive conclusions, but the TADs are warmer amps that lend a "tube like" sense of musicality. The BC sounded more neutral. Preferences for one combo vs. the other would fall under "personal taste". (I've used Quads with extended bass to describe the sound of 100s with neutral amps like the BC. Add a just a smidge of Vandy-like warmth/sweetness to the mix for the TADs.) Again, take this with a grain of salt - listening was brief and, in this case, in 2 different rooms.
With subs,
I never used the BC amp. The TADs worked very well in this configuration for a month, buefore i subbed in my Prima Luna monos with (eventually) KT66s. These add more "texture" and a greater sense of soundstage - especially between performers. This effect is evident on many - not all - recordings. It is dramatic on some. There are tracks on Lindsey Buckingham's "Under The Skin" on which this combo "lights up" the front of the room in a way I've never before experienced in my home. (I have heard MBLs manage this trick at a dealer's showroom.)
Other output tubes have been through the rotation and caused more problems than benefits in a subwoofer set-up. I will eventually work my ARC VT-130SE into the system for more perspective, but that's for another day. I'm just enjoying the PL w/KT66s too much to play around (for the moment).
Marty