There really is no hard and fast rule here. I have researched this a bit for something I was doing about a year back and it is clear that you can talk to a number of different people about their experiences at FTA A and B and get very different responses. You need three things to come together, the student, the instructor, and the FTO. Any one of those not being appropriate can reduce the learning.
Sadly as individuals we are all different so require different FTOs and Instructors. The only advice worth listening to is someone who thinks and acts like you. Someone who has the same time constraints, the same learning capacity, the same attitude.
At a rough cut level you can probably pick up some pointers on where not to go but beyond that it is really difficult. If you have got something that works stick with it. The right combination is worth far more than saving even £20 an hour.