I read a user review somewhere and he said you cannot use the reverb and chorus at the same time with the Peavey XXX Super 40 EFX. Is this really true?
If I remember correctly, each channel has it's own reverb and the effects are separate. So you should be able to use both at once. Don't go off of reviews.

By the way I tried out the Mesa F30 and the Mesa F50 (in case you remembered my other threads). The F50 sounded better, but neither of them had enough gain for metal for me. But the cleans were awesome. I tried adding an OD in front the the preamp, but it did not do much. Now, I found a Peavey XXX near where I live, and I hope I will not be let down when I try it.
The F-Series amps didn't have enough gain? Sure they do. I know a few people that use the F-Series amps and get some really heavy tones out of it. My guess is that you didn't crank them up at all. An OD in front of an amp at low volumes isn't going to do a whole lot other than add more gain to the preamp section rather than push the power tubes harder since you're barely pushing them as it is.
Well, the B-52 AT112 was played at a lower volume and the gain was higher than the F-Series. I effortlessly was able to do pinch harmonics. Besides, the F-30 is a little out of range, and I want something lighter than an F-50, so my best bet is to try the Peavey XXX. One of the guys working at the store where I tried the F-Series said that cranking the amps won't do too much to overdrive the sound a lot. Maybe the F-Series does have a lot of gain, but it does not have enough gain for extremely heavy sounds with squealing pinch harmonics. Anyway, I am glad I tried the F-Series out before I was going to buy it.
The guy you talked to was wrong. Mesa's sound a lot better when cranked, you really need to put those power tubes to work. Cranking a tube amp will lead to power tube saturation, which is what every guitarist prefers. Pinch harmonics is all technique.
Yeah, but the XXX has a broader range of sounds due to its active EQ on the ultra channel. And you have to agree with me the XXX has more gain than the Mesa F-Series.
The XXX does have more gain than the Mesa, more than you're going to need. The active EQ on the Ultra channel is very sensitive, you'll have to spend more time tweaking that channel.