For every guitar player reading: congrats, you're the weirdo who wants a Ring Modulator. It's loads of fun, somewhat complicated and often very annoying for your peers.
I've owned this since Christmas, am a serious pedal geek, and am sometimes utterly lost in what I'm doing on this thing. It's loads of fun and you could easily base half your FX off it (Vibrato, Chorus, Trem, Pitch Shifting, Ring Mod) and just run an OD..but I doubt anyone buying this will. It's a real geek's pedal, and as such it's very eccentric.
Trem and Vib effects sound great, really lush. The Ring Mod is versatile and the tuning thing is amazing, being able to change it on the fly is a lot of fun jamming! The pitch shifter algo is good, and the formant shifting keeps it sounding reasonably realistic.
Downside? For a recording band or gigging band, the controls are a bit of a pain too. It's very easy to knock the controls or otherwise end up on the incorrect preset, which can result in awful results. Make sure your feet are sufficiently fancy. I do wish it had a manual mode switch or something equally as unlikely to be hit by my foot and cause mishaps.
I think in a studio it's great for ideas. You can do all sorts of cool stuff that will often be useless but inspiring, and some genuinely useful stuff (Organ impersonations, trem, vibrato..Devo style guitar solos) but at the end of the day it's a pedal for those interested in unique sounds. I spent years debating getting this. If you want it, get it. It's always fun. Just don't expect your band to be all "Hey, turn on your Ring Mod again! Set the frequency really high".
You will, though.