I use this SR-10 in my Edge 540 for dual elevator servos. I haven't had a problem with it holding it's trim.
Price is slightly offset by the fact that the cables reach 24 inches long, so you don't need to buy additional extension wires to get to the tail mounted elevator servos.
I use it with my Futaba 6EXA-S.
7C looks cool.
Too bad you have to spend $300 on a 9CAPS to get transmitter based P-Mix Linked Trim ... make that $400 (I don't see the transmitter only package at Tower any more). Heck, might as well spend $500 and go synthesized!