I got to throw a red Amp marked 174g yesterday against a Volt and my Rivers. At first, it was definitely more understable than I thought it would be-definitely more than a River and even more than the Sidewinder I've been using for a year. It took me three throws to dial in on a laser straight hyzer flip that probably went 350 (a total guess); in a slight headwind the Amp locked into the straight line, but turned over off the flip toward the end of the flight and flexed back for an extra 20' or so. I threw that same shot with my River and it wasn't nearly as long, and didn't need nearly as steep a hyzer. The Volt seemed too different a disc to benefit from comparing it with the Amp.
I really liked the ease with which I could dial in on that line, and I'm thinking this disc might replace the Sidewinder and maybe even my Rivers. I don't throw a Volt because that slot's taken by OLFs and Teebirds, but this Amp might fit in. It was fun to throw and very workable for my noodle arm (I max out at around 375 golf d), so I'll probably be picking one up.