Surf Champ / Surfer is probably the best multi-player Gottlieb EM made in the 1970s. If this specific machine is in decent cosmetic shape (backglass art and PF are still pretty good), then it is well worth fixing up.
As others have noted, for a project machine like this, a full mechanical rebuild is the best way to get the machine back to factory-spec playing condition, and to keep it working trouble-free. That is a good choice for someone who wants a great-playing vintage machine, but who has no interest in working on pinball machines. As others have noted, you should expect to be charged $800 or more for a full rebuild by a competent professional EM tech. You have every right to expect an excellent result for that kind of money, and you should get back a machine that looks good and plays great for years to come.
If you want to learn how to fix the machine yourself, then you are highly encouraged to do that, and yes the EM Pinside folks will totally support you as you learn. You should not expect your game to play great or to be free from frequent breakdowns if you go this route, at least not for a while. That may not sound so great, but if you have any interest in working on vintage mechanical machines, it's actually a pretty fantastic hobby to get into. There is a lot of satisfaction in bringing a vintage machine back to life.
- TimMe