zenaxe
Fractal Fanatic
Flat SS Power > Tube for AxeFx. IMHO. Tube is just going to collide with the Axe's power amp simulation or force you to turn it off. Some people like them cascaded but I'd rather have an authentic simulation and clean, flat, power with high headroom to get the most from the sims. Plus you get the weight and maintenance benefits of SS.
YMMV
YMMV