The only thing I can suggest is give it a whirl.

I suspect that a lot of the servo's come out of the same factory anyway. Other than the electronics, the Esky, JP Twister and HS55s are, as far as I can tell, mechanically identical, so the gear sets between these are interchangeable!

I have used all 3 sorts on my Twister 3D and HoneyBee CP2, and TBH I'm not good enough to tell the difference. What I have noticed is the HS55 gears are maybe a smidge more robust in little knocks.

I went for the branded HS55s because I was hoping for better crash resistance. The old saying "buy cheap, buy twice" maybe isn't true, but I'm sure at least one of my crashes would have stripped gears on the cheaper servos, but the HS55 gears survived.

One way to think of it is to not go to the Student Union one night, and the beer money saved could go towards the heli (Though casting my mind back to my student days I think this would be difficult )