I bought one of those, too, to give some space to the tones from my Valve Jr. As you know, it's very cheap as reverb pedals go, so it basically only has one sound and it'll never be confused by anyone for a Fender reverb tank! Actually, the effect it produces sounds more like a slapback echo than true reverb. I read where somebody described it as sounding like "playing in your bathroom", and that's a pretty good characterization!
I found that if I set the Mix knob somewhere between 11 and 1 o'clock, I get a fairly useful tone. Lower than that and it really doesn't add much of anything; higher than that sounds very artificial to me. As far as the Hi-Cut control goes, just twiddle that to taste. I leave it right around 12 noon.
If you're looking for high quality reverb sounds that will at least approach the quality of a good tank, you'll need to spend quite a bit more. The Digitech DigiVerb gets consistently good customer feedback, but it'll run you $100 new....