I have two sets, the cream and red and the blue and silver both with their matching engines. I'm not sure what problems you might be talking about. I have found no problems with them. The only "problem" that I would call generic as you say, and it seems to occur often is that many pieces will have a paint chip or two somewhere on the body. Usually not very noticable but it's something to be aware of.
Anyway, about those types of cars, they have very nice proportions which is why I have two sets. I also have a set in standard gauge and I really like them. I'm still looking for the matching standard gauge engine to go with them though.
Good luck,
John.