I have borrowed a Boss Fender FVR-1 from a friend because I am currently using an amp with no reverb or tremolo and I like to use both. My take on it is the reverb is okay, nothing like a real Fender, but it is passable. The tremolo is not good at all. I am not sure how to describe it, but it just sounds funky (not in a good way.) The pedal also has an overdrive function that I do not care for either. I will try it again at my next gig, but with unity gain setting and hopefully it will sound better to me.
My advice is there has to be many better pedals out there for reverb, but in a pinch it works okay.