I spend about 20-25 nights a year in OKC over the past 5 or so years . The Waterford is my preferred hotel... hands down. I also get it a great rate. It is smaller than the Ren and OKC Marriott, but includes a great restaurant and bar area, smallish conceirge lounge and a very good workout club in the basement. It is also located in a residential area, so it is very quiet. It is about a 10-12 minute drive from the Waterford to downtown. Second choice is the Ren....but it is always tough to get a room. Great location next to Bricktown (ball park...plenty of restaurants and bars). I hear that the downtown Courtyard is very nice...but have not stayed there.
The OKC Marriott on Northwest Highway is a typical highrise with a JW steakhouse, good sized rooms, and a nightclub with entertainment on a regular basis. Decent workout club also.
In OKC you are never too far from a chain hotel or chain restaurant.....a couple of recommendations to eat... Deep Fork Grill, Cattlemens, to name a few.