Firstly, it is in distance learning (about the ATPL) via CATS. I heard that they don't provide any book to study. Is it true ? Everything has to be performed online via CATS ? Do you know if books and course ground school of CATS are good ?
I don't know anything about it, but I am sure that the only important thing to have success in the JAA exams is tu study...in particular the database questions. There are many available, even a free one.
Secondly, you have to go to Florida to do exam and therefore, you have to spend more money in plus of living cost and so on.
True, but in the USA if you book with a good advance (that would be your case, since you know so early the dates of your exams), the prices for plane, hotel etc are not expensive.
According to you, is it possible to pay not more than 50k euros (training + living cost) ?
At skymates you should be fine...just focus with studying!
Is it a good training to do it in USA although if I want to get a JAA licence ?
Absolutely yes! To fly in the USA it's an incredible experience, all European guys who fly there are impressed. Plus, the training is usually better, more pointed straight to the result rather than reading boring books and the facilities are much newer and better (ask some friend who flies in EU if he have haver flown a GPS RNAV approach...).
I would like to know your opinions (quality/costs) about it, if it is better to do the training in USA or Greece ?
USA forever!