I just looked into OfferUp and found a heck of a deal on a grill - just the one I've been eyeing! I conversed with the seller and then found out she had recently moved across the country and forgotten to update her OfferUp profile, so her listings still showed up in my area. Bummer! Someone in Virginia is going to get a great deal on a grill.
Overall, I do like it better than craigslist. It's easier/more fun to use, and it does seem like it filters out some of the flakier people you deal with on craigslist.