The Marriott IAH is fine, just two caveats.

The laughable little train doesn't take luggage trollies so if you have lots of stuff you'll be carting your bags around. Annoying to the point that taking a shuttle somewhere else wouldn't have been any more hassle. The food in the hotel is unsurprisingly very overpriced and quite crap. The landside areas of the airport are similarly devoid of decent eating options.

Assuming your onward flight is on CO you'll be flying with the best of the North American airlines. If you have BD miles kicking around you might be able to pick a good value C redemption.