For Eurocontrol MASUAC you can find the basic salaries here:
EUROCONTROL - Frequently Asked Questions on Air Traffic Controller Careers
Single expat:
Air traffic controller: € 4232
Working shifts entitles staff to payment of a flat-rate shift allowance which is set at € 1425 for those working a 24/7 shift
Lon More: now you're only entitled for a tax-free car if you actually reside in the Netherlands - if you live in Belgium/Germany you don't have this option.
Surferboy: I don't think there's gonna be any conversion training in Maastricht anytime soon - since the last one was (again) not too successful - many of those guys couldn't finish the training, so I seriously doubt there will be an other one for a few years at least...