I was in Naples earlier this year, I spoke to one instructor of NAC who was thinking of leaving, and one student who had failed at least 3 ATPL's on their groundschool.
They sound like a cheap option from the outset, but there are added charges here there and everywhere, however if you go there with the focus to pass everything like every other school you will do okay, just be prepared to have scheduling issues, taking longer than estimated and lots of different instructors. Also do not pay up front!