Robust Boss housing has a collection of very usable and clear soundin digital reverbs. Nothing really special or exciting - well, some attempts at it - but well executed and reasonably priced for the quality.
RV-6 has all the controls your basic reverb needs: how much of a reverb you want to mix in your sound, how dark or bright the effect should be, and how long a tail it should make. The modes are technically all usable, though it depends on your personal preferences and taste how much so.
I've ended up using RV-6 as my base mild reverb. In this adaptation the spring, plate, hall and room modes are all very usable and tweakable to my liking. When experimenting with other settings, they haven't been quite my taste, and in the case of Shimmer I've actually found the sound pretty awkward and borderliing horribly artificial. Dynamic mode is pretty interesting, just not that much my thing in the adaptation I use the pedal, and the +Delay mode isn't as twekable as the separate delay into reverb would be. Personally I just don't like modulated reverbs much, but there's nothing wrong with the execution here, IMO.
I'm seeking an applicable pedal to replace this one in my rig, preferably something with less modes that does them (even) better - after all I need it for a pretty simple job so I'm tending towards simplifying things in my rig.. However, when I find what I'm looking for, the RV-6 is still a keeper for home rehearsals for its versatility and overall quality. I definitely recommend it for the quality at this price point.