In B class, I use standard servos on flight controls, usually JR 517 or 537 picked up on ebay. Throttle is an hs-81.

In A class last year, I used a JR standard servo (505 or 517) on ailerons and a hitech standard (4xx, I think, they are really old) on elevator because that's what I had sitting around gathering dust. I'll have a mix of the same this year and maybe some hs-85 or hs-225s mixed in, depending on how much of a threat Bill and Chris turne out to be. Again, hs-81 on throttle

For 2510, I'll have have the same hs-81 on throttle. And another mix of JR 5xx and hs-85 and hs-225 servos on flight surfaces, mostly determined by my cash situation.

Oh, and lots of spare gears for the hs-81. Some guys use the hs-81 on flight surfaces in A class around here, but I personally don't trust it for that.

Oh, btw, I'm not claiming my servos are the best options. It's just what I have been using and what I'm comfortable with, and what I have spare parts for. I was thinking of going to more hitech standard servos, but keeping spare arms, gears, cases, etc stocked for too many servo models is a pain.