I have now finally received and approved test prints from both Lulu (the left one in the picture) and DriveThruRPG (the right one in the picture). I think the cover from Lulu looks better, but the paper quality of the actual pages might be slightly nicer from DTRPG. For me, living in Sweden, Lulu offers much faster deliveries since they print within the EU. But I suppose that may vary a lot depending on where you live.