The double sheets are too thin to be the only covers - blankets/comforters need to be added. I agree with all of the complaints about the lack of blankets on the bed. Great view from our room on the 22nd floor. Parking garage a bit of a hike from the hotel - but that's not at all rare in casino resorts. We arrived a bit early and had no problem checking in. The hotel, common areas, etc are very nice since it's all relatively new.
It was a family trip to Tulsa - we had our elementary age kids with us. We went to River Spirit for 5 nights in March. We really enjoy River Spirit overall as a resort and would definitely recommend. Overall my thoughts below are still the same (including the fact that after being there 9 nights now overall - we can do decent on the River Spirit side - can't win anything on the Marg side). They've done a nice job of making it accessible and fun for all ages.
We had a fantastic time at the swim up bar, tiki restaurant etc. We've since gone back just a couple of weeks ago without the kids. I posted a review under River Spirit after we went in March - but since Bips mentioned it - I'll paste it here too.