Answering your question: no, it's not a good school.

ATPL groundschool is fair. Just fair. Books are of poor quality, lots of factual errors. Considering you don't really need neither the books nor the classes to pass the exams, it's better to save some money and attend some distant learning course. I heard Bristol is pretty good. Most of people use their question bank anyway to prepare themselves for the exams. Concluding: modular course is NOT a waste of time, though it's definitely too expensive and I'd expect much better quality for this money.

Flight Department... A complete disaster. To cut the story short - you don't want to fly there, believe me. The quality is absolutely below any acceptable standards. Once you pay upfront (which is required in so called "Career Pilot programme"), the nice picture ends and the good impresion's gone. The school is an excellent example of a very poor organization, really bad attitude and disrespect. Lots of hidden charges and unpleasant surprises, which will cost you much more than you originally planned to spend. If you question anything, or if you want to build your hours elsewhere (= cheaper), be sure NAC _WILL_ cancel your visa and keep your money.

Literally next door there's another school, Europe-American Aviation. Go there, without a doubt. After I had quit NAC I flew with EAA and there's absolutely no comparison between these two. My experience with EAA is absolutely positive, the airplanes (diamonds - DA-20, DA-40, DA-42) are really nice (all 40s and 42s equipped with G1000 glass cockpit), very modern and well maintained. The personnel is friendly and very helpful. If I'd known earlier, I would've gone straight to EAA instead of wasting my time and money at NAC.

My advice: do your PPL(A) ICAO at EAA (or any FAR141 American school, but DO some "quality research" first!), build hours wherever you want to (at least 150 total/100 PIC for JAR CPL), you can also do your ME rating in the States. Then do distant ATPL and - with all exams done - convert your license to PPL(A) JAR. You can continue your training in Europe (IR, CPL(A)) or in some other JAR-certified schools in the States (be careful though!). Though you can do IR in the States, you still have to do a conversion in Europe, so you might as well do it from scratch in UE with your PPL(A) JAR.

Just for everyone out there that is right now considering NAC as a potential school to train - here is my feedback.
Personally, I had absolutely terrible experience.
Went out there to do my CFI training and regretted later. Flight instructors and maintenance department do what they can and there no complains about them. However the school management and the front desk could serve as a school book example of how you should not do business. Horrible customer service. For example I had multiple occasions when I could not get the dispatch sheet/ get fuel/ or other supplies: no one would be at the front desk for 30-45 min because they have a meeting. And when you have specific plans 45 min delay can be very frustrating!
Advertised price at the web site is one but when you get the invoice you find out that there is a fuel surcharge of 25. And many other small things that add up and make a bad impression.