Air retracts work fine but they are a PITA to maintain. Micro leaks are hard to troubleshoot. Tubing and valves all over the place. You need to pressurize an onboard canister, etc. Servoless types have come a long way in a very short time. All metal with metal trunnions and 5mm pins. Slip fit spring loaded oleo struts. Nice.
They now make them for planes weighing 30 pounds. I think the heaviest plane I have is about 7.5 lbs. You do get what you pay for IMO. The expensive Robarts are well? Robarts - LOL I'm good with the HK's for now. Should hold up for my lighter applications.
I don't want to end up paying more for the retracts than I did for the plane.
Adding Exceed 660kv motor ( a 46) and 85 amp esc. Will run 5S.