I fly into Aachen a lot, it's a really short runway and requires a careful and stable approach and landing. It's uncontrolled and has no navigation aids.
Maastricht is by far a better choice but then again, I'm prejudiced since I'm local. Long runway, ILS on both sides, VOR and NDB's, ATC, hangars, food, the lots.
Maastricht City is the oldest town in the country, built by the Romans together with Aachen. Valkenburg is only a 10 minute drive and has a great Christmas market and other places of interest, caves, castles, casino. There's something there for everybody
. Terrific selection of hotels too.
Mode-S and 406-ELT is required in Holland but I may be able to get you a waiver for the aircraft that are not equipped according to Dutch law. Drop me a PM if your club decides for Maastricht and wants a waiver..
