This is largely an arithmetic problem. Look at some destinations, and find competing hotels in the price and amenity range that you would typically stay. Look at the corresponding hotel program (Choice, Hilton, Hyatt, IHG, Marriott) to see how many points are required for an award night at that location. This will allow you to assign an approximate relative value to the "points" issued by each program.

Then, look at the co-branded credit cards for each program to see how much spending is required to earn an award night.