Still haven't had the chance to try out the GT-6, but if I've understood correctly it's actually a cheaper box than the GT-5. The GT-5 is a very good effects box though, with a huge range of sounds that can be coaxed out of it. Used equipment is a good idea, but with effects it is important that nothing has happened to damage the circuitry, and that none of the input or output jacks are stuffed. Be hesitant about buying second-hand over the net unless it's from a music store or someone with very high feedback ratings. Otherwise, you'd probably be able to find some second-hand stores near where you live. You might ge lucky and find something you like.