This year I went through FAA NDT & Composite (including inspection and repair) classes and as a result would be much happier purchasing a metal used aircraft over a composite one.
I was at Socata's factory a couple of years ago, and they showed a small crack in the composite roof, near one of the door hinges, caused presumably by somebody allowing the door to be grabbed by a strong wind.
The man explained how the repair is done... in multiple layers, and it takes several days, and no doubt costs thousands.
With a metal hull, you just rivet a reinforcing plate in there.
Same issues with installing GPS and VHF aerials. If one has a uniform composite hull thickness of say 4mm, one can't just screw a big rod aerial into it (Vne 189kt). I looked into this once and there was simply no approved procedure. Socata provide two scallopped-out aerial locations and that's your lot.
Metal repairs can also be easily inspected.