Hi Killua,
I am sure the answers are out there somewhere! But I will add my opinion anyway.
1+4 - Working in Maastricht is generally good ( every company has certain issues) We work with one of the most modern systems in the world that is constantly being updated and upgraded with a lot of money being invested in it.
The shift pattern is 4 on and 2 off, all shifts are 8 hours long with 30mins. of that being briefing time ( unless you work in the Hannover sectors in which case you work 2 hours per shift - it is safer for everyone if they aren't there for long
). We can work maximum 2 hours in a row without a break and 25% of working time is break ( during the day - 33% at night).
The rest and sports facilities aren't the best and we keep being told that they are going to be upgraded but nothing has come of it yet
2 - Maastricht is a nice enough city, fairly small and doesn't attract a lot of big city companies or big events - it depends where you are from and what you are used to, but there are plenty of other options in the area. Dusseldorf, Koln, Aachen, Liege, Brussels and Eindhoven are all within 1 hour drive and there are reasonable transport links.
3 - the salary sounds about right, but you will get shift allowance and various other benefits which means after qualification you will start on around 5 - 5,500 Euros per month which is more than adequate to live on if you compare it to the average local salary of +/- 2,000 Euros. Also you have a guaranteed promotion structure which means you will get regular increases
Hope this helps.