I've been looking at this as well in light of what would work best for me.
There are really 2 different point awards methods. The "triple points" is a straightforward bonus calculated by room rate times nights. The "free nights" is really an 8000 point guarantee for 2 stays.
The real kicker is that multiple night stays have a massive negative effect on the value of the free night option.
If each stay is 1 night, the free night option basically gives you a 4000pt/night guarantee, as you need 2 stays to qualify for the 8000 pts. If each stay is 2 nights, that is 4 nights to qualify, and the guarantee goes down to 2000pt/night. If you go to 4 night stays, the guarantee using "free nights" drops to 1000pt/night.
If you do the one night stay method and select "free nights", the only way "triple points" earns more is by paying $133/night, every night.
The way to maximize points per dollar spent is to select "free nights" and always stay just 1 night at the cheapest location. Or, I guess you could go with triple points and pay more than $133/night, but then (as previously mentioned) why stay at a choice property?
Sometimes it is a pain to pack up and move out each morning, but the points can really add up fast doing it that way, and that is what I plan to do.