I've bought several of these servos and, when they're working, they're great. Unfortunately, with the slightest amount of wiggling of the wires, they break off where they meet the board. Because this location is covered with rubbery insulation, one cannot see the condition of the wires. If this problem was fixed, I'd have no problem with these servos.
Needed replacements for my UMX B-17 aileron servos. Fit was exact but leads were too short. No big deal, just spliced a piece of the old servo wire to the new one to make it long enough.