I agree with every word from EHRD-0624.
HHN is an X american airforce base but since reverting to civil use it has grown and improved with every month. The service is second to none compared to FRA, everything is close to hand, so no long walks. All the airport staff are very friendly and helpfull.
Yes there are no trains to HHN at present but the structure is there, and as for the road, the E50 goes to LUX (70km) in one direction, and connects to the motorway A61/E31 in the other, most of which is 4 lanes.