IMO peavey drive on the ultra series ( XXX probably the JSX too) have very grainy distortion. The drive is very loose and a bit shrill at times. The Ultra series has WAY too much gain on tap but I would probably recommend the Ultra plus or the 60/120 watt combo over the XXX. I ran a good tube compliment in my XXX head but was completely floored when I bought my first triaxis. Now I have a Mark IV, a triaxis, and a line 6 spider valve combo.
The line 6 isn't bad for the money and you can't beat the features but I sure do prefer the TA or Mark IV to the line 6 when it comes to sounding like I want it to sound.
If you want to stick with peavey then check out the Bravo for a small but toneful amp. This amp is based off of the Ultra series as well and has a 25 watt EL84 power section. The subway rocket is cool , DC3, F30, etc etc. You have tons of options it just depends what you're looking for.
Maybe even going with a good solid state amp would be a viable option for you.
Greg