I agree with Larryz on the 40 watt, unless the 80 was some compelling features that the 40 does not have.
I've only used the 50 watt setting once, at an outdoor gig. For lots of other gigs, 1/2 watt was plenty. The line out into a DI box then the PA sounds great too.
I am afraid of the 100 watt setting, probably way too loud!!!!!
Kuru, I should clarify my comment on my 100watt SS amp. Per Fender it's actually "100watts into 80 (simulates a 22watt tube amp performance)". The highest setting on my amp is 22watts. The lowest is 0.2 watts. +1 the 22watt setting is way too loud for most venues and I run it at 12watts out of the home at gigs/jams. At home, I always run it at 1 watt in the bedroom and it's plenty loud. I never run the volume knob past 4 and I still have to turn my guitar down LOL!

Great stuff Larryz1
And that feature alone has me sold on using the modern solid state guitar amps.
In addition to the Katana I have a Peavey Vypyr VIP3, it's a bit bigger and heavier so I've got it mic'ed up for studio work.
The last knob to the right is called "Power Sponge" and it lets me set any variation from 100 watts down to 1 watt. I LOVE it at 1 watt, it's still pretty loud but you can hear the difference that output section saturation simulation makes and Peavey has gotten that right with this amp.
The biggest problem I've had with tube amps is most of them are way too loud when you turn them up to where they sound great. Gotta get that back end cooking.
A friend has a Fender Champ that he shoehorned a premium 10" speaker into more of less as a joke but he gigs with that all the time and it is terrifyingly loud.
That's only around 6 watts!
I'd love a half watt tube amp, just for fun.