I think it's a great deal for a starter game. Nice shape with new rubbers and lights? And in your area? Sign me up. Pinball is all about finding the right game in the right place at the right price.
The 10 point relay is almost certainly a stuck switch behind a rubber. The person who put the new rubber on probably had no idea what they were doing and didn't check to make sure the new rubber wasn't closing a 10 point switch. This is very common.
Fix that issue ASAP or you will burn a chime coil and a score real coil. Should be a very easy issue to sort out. You can't play the game until you fix this.
I don't see why you'd pass on this. It's dirt cheap (worth more in parts easily) and it's local, and it sounds like it matches what you are looking for. I've owned a few Big Bens and it's a fine looking and playing EM pinball game, perfectly enjoyable and if you decide to dump it at $250 you'll have no problem getting your money back out of it.
Buying a dirt cheap EM that nobody likes as your first game was once a rite of passage in pinball, before entering the hobby meant spending $9,000. Bring back the tradition!