I'm using the first gen Vox "Metal" it's decent and maintains note definition better than some of my amps. Has overdrive, tone, vol, and aux input. Clean(OD down) is muddy and lackluster, though. I've tried pretty much all the Amazon brand ones, and can't personally recommend any off the top of my head. Also plays nice with neutral/studio headphones, not so much with ones leaning toward bass.