I guess it all depends on the ARF or KIT in question.

I do feel however, that everyone should have build a kit somewhere down the line, just for building experience. Even with an ARF you'll have to do some (re)building sooner or later, you can't just go out and buy a new ARF everytime something breaks.

I would recommend buying an ARF for learning to fly and just messing around. This advice is based on the fact that an ARF is easy to replace.

I have not yet seen an ARF that is really well build all the way, but most are sufficiently built just to fly with. They may not be perfectly glued on every join, but who cares if it flies fine and you never notice that.

I use a ARF for everyday flying and a kit for scale fun and so on.