Lived and worked in Maastricht from 1997-2004 and loved the place. Only went for 3 years initially, but stayed seven, which says something. The old town centre is great, the restaurants and bars as good as anywhere in Europe and the Cloggies are generally good eggs. 99% of them anyway. House prices were quite reasonable back in 1997, but had more than doubled by the time we left in 2004. Equivalent to UK 'home-counties' prices.
A lot of people moved just over the border into Belgium from 1999 when the Dutch tax authority allowed mortgage interest tax deduction on Belgian mortgages.
After the first year, we moved up to Margraten in the 'mountains' or heuvelland. I'm good with languages, but it still took me 3 years to get to grips with Dutch expecially the Zuid Limburg 'Dialekt'.
I think Eurocontrol pay their salaries net of tax. If not, you can get the 30%-Rule or 35%-Rule as it was when I arrived. This meant the TOP 35% of your income was disregarded for Dutch tax. Also you can park any savings offshore if you register with the Belastingdients as a 'Non-resident Resident'(!) A bit like the UK non-domiciled status.
I'd certainly recommend it.
