I did a bunch of searchs on R/C uniuverse here to find out using the dig Hitechs cause i wanted to use them on my katana, It seems there was a problem with some of the first 56xx series but that was at least 2 years ago. There also seemed to be the concenous that the 56xx series has a voltage drop problem with using long servo extensions and 4.8 volt packs, going to 6.0 volts seemed to be the remedy and nobody using that setup has a complaint. Most every body had nothing but good things to say about the 59xx series digitals and even though they are 25 bucks more a pop thats what i went with, 5925 on all the control sufaces.
I love them so far, 3 gallons of fuel thru the plane with no problems, not a real test of longevity yet (but I was apprehensive at first) so I really think they will be okay. ok enough that i bought three more 5925 and two 5975 (karbonite gears) for the CAPX.
If I have any problems I will let you know. Its hard to justfiy spending as much on servos as on the engine/airframe but when you consider what you might lose buying on the cheap, i think its a worthwile investment.

zonk