I use most of the mahorse ones depending on what city I am staying in and the area I want to stay. My most used are Choicerewards.com and Hiltonhonors.com. At 600 an hour, most choice hotels should not meet your standards. I am more of a "if it is clean I will stay there" type of guy. I found a motel in Western Kansas that is $35 a night. I think I will drive a few more miles. It will not really matter as there are no providers in the middle of nowhere.
I use both Choicerewards.com and Hiltonhonors.com often and belong to both the major Vegas reward programs Mlife and Totalrewards.
I prefer the Hilton line just because the properties are usually nicer and if the owners let them run down they lose the Hilton tag (Looking at you Little Rock). Choice seems to rack up free rooms faster stay twice earn a free room, but its a lower tier rooms except for the Asend or Cambria lines.
Similar to airline rewards, it depend where you intend to use it the most. In my opinion, Marriott has one of the best all around values, in terms of earning reward points and redeeming reward points.