I have had my GNX4 for about 8 months now. My only complaint is that most of the presets suck! I have my GNX4 plugged into the effects loop of my B52 Tri Rectifier with a 4x12 cab, also B52. Some of the presets give off a terrible buzz or feedback. I have tried adjusting input gains and the level on the GNX4 itself but no luck. It's great if you want to sit and play through headphones but I don't think it's all that when it comes to plugging it into your amp.