Loads of versions - original was great for PA, for a bit of reverb, of effects, then the later versions Mk2 , 3 etc got better and better. £60 is not that cheap of course - I've got a rack full of reverbs, compressors and gates from those days - not even quite sure where it is now, but my studio in 96 had quadraverbs in the rack. It makes nice noises - it doesn't like anything other than line in - trying to use them on guitars reveals the noise.