I'm training with LFS and really enjoying it. Friendly atmosphere and great instructors. I also get the impression the fleet is well looked after, with all of the aircraft being hangared overnight.
Had a friend do an instructors rating at Ravenair and he was very complementary about his particular instructor.
Only experience of Merseyflight is that they nicked some of my photos for their website, so not a big fan :P
Heard good things about Lomac aviators but no personal experience.
EGGP is a nice place to learn, but not the cheapest. Landing fees are quite high and you often have to hold for IFR traffic (had one 50 minute lesson in which we only did 2 circuits!)
.mic