There's a lot to be said for doing it full time as you will be more focussed. What you must be prepared for is that this is more like being at university than being at school - no-one will spoonfeed you - it is up to you to read around the (huge) syllabus to get the full picture in your head.
The schools can help you focus your studies based on their feedback from exams, and of course can assist with assessing your progress, but no-one is going to offer the exam knoweldge on a plate. It's not the FAA ATP's sadly.
IMHO they should make it so that once you unfreeze your ATPL you should be awarded with a bachelor degree, becuase it's the same level of achievement.
cheers!
foggy