I originally did my PPL training with Cabair at Denham back in the eighties. Since then I've done the typical thing of letting things lapse and going back for more training a number of times, so I've flown with quite a range of different schools - one other at a west London airfield, one at Biggin, one at Elstree and one of the highly-recommended ones in the US.
The conclusion I've reached is that Cabair are undoubtedly expensive - and sometimes they really take the p*ss, which is why I think they're so hated - but the standard of training I received there was undoubtedly better than anywhere else I've been.
Having said that, I'm not sure how much of that was Cabair and how much was the CFI-effect (who was David Hoy during my time). The one common factor in all the schools I've trained at is the atmosphere and professionalism of the whole school does very much reflect its CFI. Maybe because certain setups attract certain people or maybe the other way round - after a while the CFI leaves his or her mark. There's definately a correlation though.
I'm currently pondering where to do my IMC (any recommendations gratefully received!) and because it's new stuff - not a revalidation - I really feel I need to be taught it properly. It probably won't be Cabair this time, but they'll make the short list.