The Univalve is OK. However, it doesn't have reverb and can be a very unforgiving amp. Good if your looking to improve your technique. But you have to be on every time you play this amp. If you have an off night it will really show. Maybe that's why a lot of people use it as studio amp. It has taken me months to get used to this amp. Also, it's only as versatile as your pockets are deep. Get ready to spend more money for tube swapping.
The Blues Junior or the Peavey Classic 30 are plug'n play amps and you can upgrade them. What's cool about an amp like this is whatever is in there is easy to get at.
With the Univalve I go through a lot of wondering if I should be swapping tubes to get a better sound and playing with the dials trying to understand how they interact. Messing with the built in hot-plate or turning off the built in noise reduction. Messing with my volume & tone nobs on my guitar. On average I spend the first 30 minutes of each session getting the sound right.
I'm not an expert on amp setting and it may be easier for other Univalve users, but IMO this amp is for people who like to tweak & tweak & tweak their amps. I getting to like this amp, but it's been a journey.