I have a $100 amazon one, a Theragun mini, and often use a friend’s Hypervolt 2.
- The name brands are a bit better built, less flex/creaking
- The amazon one is actually the quietest
- There is a little bit less strength on the Amazon one (but I will pretty much use any gun at max power 90% of the time)
- 20 speeds on the Amazon one mean 1-10 is useless 15 - 18 - 20 are closely matched to the legit ones three speeds.
- Battery life is similar across the board, good enough for a week of use between charges
- Theragun Mini is by far my favorite, the key is the smaller size allows me to hit my legs on a long drive home from a mountain training ride or race.