Both are really solid choices in my mind. Both very fun, but flawed games. Ripley has the deliberately weak upper flipper, and I think some other clunkiness on the table. Gofers code isn't good. Both are really fun, despite the issues.
Gofers has more flow, better theme and humor, and one of the better toys in pinball. Ripleys, on the other hand, has a classic Lawlor layout, some of the best stop-and-go play out there, and will make you a better player.
If you're buying something to go in a larger collection, for the family, or like toys, go for Gofers. If you want more of a challenge, or you host any pinball leagues, go with Ripleys.
I own Gofers, and have had a decent amount of time on Ripley. I would've been equally inclined to buy either. Gofers made it into your collection because I found one at the right place and time.