Pro reverbs are amazing amps. Take a step back, the Fender Twin is the penultimate Fender vibe/tone, but they're just way too loud and heavy to lug around. The Pro Reverb solves this. They're a bit lighter in weight and a more manageable wattage. These bigger Fender amps make cleaner tones sound magical, something many other amps can never quite capture.
All that said, I really love the late 70's Pro Reverbs - big ass clean tones that break up just enough when you wind the channel volume up. They come to life with the MV on about 3 or above. The reverb and trem on old Fender amps is just divine.