I have an old Hangar 9 Easy Fly 40 ARF that I'd been flying up until this spring. The wing sits crooked in the wing saddle, the verticle and horizontal stabilizers are all crooked, and the landing gear is bent up. Nothing on that plane looked like it was supposed to. It sure flew great though.

I replaced it with a new Tower Trainer .40 MkII ARF this spring, however, because I just couldn't stand to look at it any more.

Generally speaking, however, if the plane flies straight, that's much more important than if it looks like it flies straight.