At that level of hotel, I'd be more concerned about the quality of the properties than the rewards. That said, I like Hampton Inns over their competition - and the little perks you get with HH Gold actually aren't that bad. Nothing sucks worse than a bad motel, and you can usually find passable Hamptons wherever your travels take you.

IMHO, Fairfield Inns are not as consistent and reliable as Hampton Inns. YMMV. Four Points by Sheraton seems like a good brand, but I don't see nearly as many of them in the Midwest and West (my primary roadtripping country) as I do Hamptons and Fairfields.