Although IHGs scheme is not as good at full service recognition as Marriotts, it doesn't sound as if your budget is going to stretch to full service. That being the case then IHG is really worth a second look for you.

With IHG you'll find plenty of HI and HIX in your budget range wherever you are. Most HIs are pretty good at recognition providing room upgrades and a few even free breakfasts. HIX have less to upgrade to but are generally newer properties and of course their rates include breakfast. As a 75 nights "Spire Elite" you'll receive 20 points per $, and 25,000 points every year you stay top tier. IHG points redeem on a very similar basis to Marriott, but you'll earn more of them, and when redeeming IHG has some much nicer Crowne Plazas and Intercontinentals.

Marriott is my first choice but in places where I can't find a Marriott I can almost always find an IHG. It's well worth a look.