I think a lot of people forget that ALL schools have their pluses and minuses. Even people at schools costing €120,000+ have things to complain about. I know because I have heard lots of them.
The other issue is most people only go to one or two schools during their whole training journey. Very few have been to multiple to schools and are able to fairly compare. Not to pick on anyone, but look at Richard's post above. He obviously has an issue with Bartolini, but then recommends three other schools. I am certain he hasn't studied at all four and doesn't have full information on all of them. One of the schools he lists, for example, has an appalling reputation based on hearsay, but, again, I haven't been there so can't really say.
Bartolini is a lot cheaper than those €120k+ schools and also has a great reputation. Look how many of their former students now fly for the airlines. Very few modular schools can boast the number they can.
Though I am sure there is plenty of negative stuff too.
What advice can be given is that students should go into training with their eyes wide open.
Yes, do lots of online research, like on here, but take it with a massive pinch of salt. Take marketing information with an even bigger pinch of salt.
What's super important though is to visit the schools. Speak to real students outside of the earshot on sales staff. Try to talk to instructors/ operations too. Try to get a feel for what the school is really like.