I don't know, I've never used them but some ppl have reported issues of gears stripping easily. again since I don't own them i can't say for sure. if you're looking for good servos then get the hitecs with karbonite gears or the futaba 3114. they aren't digital but so what? the only heli's that i use digital servos on are my hurricane 550 and trex 600N pro, all my 450 size machines have analogs on the cyclic.

if you want to give them a try, please do so and let us know how they fare. they might do a lot better on a 300 size electric compared to the 400 size blade 400.