I think like many practices, it's a case of the individual vet you see - they can be very pricey though and I've heard a lot of people say the same! I used to go to a privately owned practice which was taken over by medivet last year when the owner retired, and the prices pretty much doubled overnight (admittedly it was cheap before!)
On the up side, they do have their own emergency centres - although they can be a long distance away - but at least it means that they have access to your pets medical records and the animal can stay there and not need to be transferred backwards and forwards. Their own lab facilities also mean that by 'sending away' blood tests etc, they still come back quickly and presumably because it's all part of the same company, they can pull strings and get results back more quickly if cases are urgent. I guess if you have good insurance, then the prices aren't so much of a problem, but if you're considering going there, I would ring up and get a general flavour of prices for things like blood tests/x-rays/dentals etc.
Having said that, we swapped practice shortly after ours changed - we had awful problems getting appointments (mainly 'teething problems' but still not helpful when you have poorly animals) and I wasn't very confident in the usual vets ability with rabbits. I moved to Companion Care, which much as I hate the fact that it's in PAH, it is open 7 days a week for routine & emergency appointments, and I'm very happy with the vets there - but again it does so much depend on how you get on with the individual vets in the practice you are at!