I agree with mad_jock; as somebody who is currently following the modular route in one of the large FTOs I am possibly slightly biased. When I completed my PPL and started hour building on my own I suddenly realised how much I had being relying on my instructor's judgement.
While hour building for 150 hrs in a 152 won't get you ready for a 737 sim check, it will make you stand on your own two feet and will force YOU to question yourself and make sure what you are doing is safe.
Most of the people following the integrated route have never flown on their own except from a 2km runway in the states with 100km+ vis. While this mightn't be a factor if they walk straight into a RHS on an airbus, for those integrated students who don't make the cut for BA or whoever, I can't help but wonder if they are suitably equipped to go into other jobs where they can't rely on EFIS, FD and the pro in the LHS.