I think I have to agree that CBR was the worst in regards to bus service, but I guess it all depends on which section you stay in. We were in Trinidad South which is apparently either the last or the second to the last "island" on the bus loop. Seems like we were the first stop for the busses going out and the last stop for the busses coming back in. I guess if you stayed on the very first "island", then you wouldn't have any complaints. LOL But it's been 5 years since we stayed at POR, so I can't remember how the bus service was there, but I do remember stopping at FQ first, and then there are different stops for Alligator Bayou, and the different Magnolia Mansions, as well as the main building. At CSR, there is the main building, plus the stops for the different Casitas, Ranchos and Cabanas. So no matter which one you stay at, there will be multiple stops. Whether you like the bus service or not I guess depends on whether you are one of the lucky ones to get put in the section where the bus stop first coming back and last going out.
You didn't say whether you will be travelling with youngsters, but here is another thing to consider if you are. We had our 2 3/4 year old daughter with us last time at CBR and we were on the second floor and there are no elevators. So I would carry the stroller up and down the steps with my daughter in it. lol Plus, it was a pain to have to carry everything else up and down the stairs with no elevators.