Most integrated schools are miles away from the efficiency of Bristol Groundschool. The ground is probably the toughest part for a number of reasons. Yes, the CPL and IR are tough in another way but the ground sucks and for this reason I would advocate all people wishing to pass the ATPL's going to BGS or suffer the consequences.
Unlike most on these pages, I have experienced both modular and integrated so am qualified to comment.
Go modular.
VFE.