You can find pros and cons about any training provider.
Make a list of your top 3-5, visit them. (unannounced) and see what kind of feeling you get from the different setups.
Look at the availability of helicopters and instructors and the price you're gonna pay (which can vary a lot).
Then at 2 of them do a short trial lesson and make your choice.
Your location might also be worth mentioning as travel time/cost might also rack up the total costs of your cpl(h).
And the type you want to do the cpl on: R22/R44/G2
If you're London-Reading area:
- Helicopter Services Wycombe
- Heli Air Wycombe / Thruxton
- Phoenix Blackbushe
Good luck.