the MAIN difference, imho which no one hardly ever mentions:
Modular means: You have to organize yourself and your training. Need to call instructors, organize your medical appointment yourself, pick the FTO for your PPL yourself, then think...maybe there's a better organisation for multi engine, enquire,............................, and so on.
It's work, active work. You have to look out for your ducks to keep them in a row. When will your medical lapse. How many more landings do you need, etc.
Integrated is largely (and I don't mean that disrespective):
Someone takes you by the hand, maybe gives you a uniform to train in, and literally walks you through the entire training until you're done. They'll make sure you do everything you need to do, have everything you need to have, make sure you know what's needed. It's less do it yourself and less planning for a higher price.
I am not endorsing either model, but (and I went modular...) in the end of the day, think about it like this:
Would you REALLY (I mean...R E A L L Y!?!) spend 100,000 (that's One Hundred Thousand) to get a license you can get for 50,000?!?!?!?
Don't get me wrong, maybe the integrated guy gets a job before I do...but 50,000 excess in cash he doesn't have is plenty to live on until you find a job.