I fly out of Redhill, renting Cubair aircraft. I haven't had any experience with Harvard so can't comment there, but would happily recommend Cubair to anyone - I don't have any connection with them other than being a happy customer. I did some PPL training with them a few years back to get a JAA PPL (I had an Australian one) and got on fine with all the instructors.
Training fleet there is DA20 Katanas which are nice to fly and will glide for miles when you do your PFLs! They also have their own maintenance facility so it is rare that an aircraft goes tech for long before it is fixed.
Redhill's runways do suffer in the wet but they have spent a lot of time and effort improving drainage which has helped a lot - and there is the hard unlicensed runway / taxiway although I don't know school policies about using that during training. Right now, the runways are spectacularly hard!
Airspace around KR can look a bit challenging, but it isn't too bad at all, and you'll get very good at knowing exactly where you are at any given time.
Paul.