Quoted from pezpunk:
personally, i recommend going with neither ebay nor a retailer, and dont ship a game. find a relatively local collector, and go pick it up. play it first, and give it a good look over so you know exactly what you're paying for!
What he said.
You didn't mention your level of knowledge when it comes to electronic/electrical/mechanical things. Pinball machines combine mechanical, electrical and (other than EM) electronic components. They were made for commercial money-making, *not* collecting or home use, and were considered *consumable* at the time they were assembled. They were also *hand-assembled* without regard, in most cases, for serviceability or maintainability and had zero, or near-zero warranty considerations (since they were commercial and not "consumer" products.) You'll find all this out with the first one you buy as you maintain and (if you're into that) improve it from whatever state you buy it in.
What this means is that while there are things that are "standard" (e.g. the size of the playfield glass on most pinballs) there's somewhat of an art to getting them running the way they should and keeping them in that condition and every machine is a bit different. In the case of EMs this is even more-so than in the case of electronic games. Pinball machines require regular maintenance and upkeep if they're going to play well, and the more they get played the more they require of that routine maintenance, although in a home it's much less than it is in a commercial location. You either need to know someone who can maintain and repair them for you (and be willing to compensate them in whatever way is required) or you need to know how to do it yourself if you're going to own these on a long-term basis. For your first one, unless you've got a fairly high degree of skill level when it comes to electronics and electrical things you probably want to buy it from a knowledgeable owner who has already done that and thus while the cosmetics of the game may be of variable state the *mechanicals and electrical/electronics* all work and are in good order.
While I know a lot of people ship these things all over the place I've never bought I game I haven't looked at in person first, and I've never sold one to someone "at a distance" either. The obvious exception would be a new-in-box one from a manufacturer, which today means Stern or JJP. Pictures cannot possibly be accurate enough to assess condition for a used pin; IMHO you need to see it.