I would say it depends on how soon you want it to be in great shape. You say you are a pretty good do it yourselfer, so I would say $600 is pretty cheap, and even if it would take alot of work it might be worth it. It may be a good summer project, somthing to fill your evenings and weekends. If I were handier under the hood I think I would go for it. Be sure the body is in really good shape. Check under the carpets for floor rust, maybe owners of this model can tell you where rust is most likely to accumulate. If the body is in good shape I think it would be worth it. If you decide to go for it, offer $400, you might get lucky.
1995 E420 - retired
1986 420SEL - retired