Well, I was in couple of "regional" airports in Germany:
– Sigerland
– Augsburg
– Dortmund
– Nuremberg
– Memmingen
– Padeborn
I'm not taking big airports into account like EDDF, EDDM, EDDB, EDDK, EDDL – all experience is just positive. I can't remember any issues. Like German cars – efficient, on-time. Slots some-time can be annoying.
Considering small regionals airports – even easier than big ones, because they normally not busy at all. There are some drawbacks in very small airports like Sigerland, Augsburg – you can't order catering. You should go to a restaurant in order to do so. Once have a delay in Augburg early in the morning, due to de-icing truck was not ready and it took 30 minutes to heat up fluid. But it's very small issues, from almost positive experience.
Equipment – all above regionals airports are fitted with ILS CAT I at lease from one side, and normally non-precision VOR from another.