I have rented from UFC and had no problems. Aircraft booking is straight forward and facilities are good. Had some flights with good instructors too. There's a hint of some internal wranglings going on but I never really understood what that was about because I generally can't be bothered with that kind of thing and that was good enough to leave me unaffected.
You could do no better anywhere than have John Phelan from Belfast Flying Club instruct you but I don't know if they are taking students - you should def find out.
If you are close to Enniskillen check Amphibious Flying Club too.