SD is not good for those who need individual health insurance plans. SD is cheaper if you are buying a rig - the sales tax is only 3%.
Texas has a lot of health plans (as does Florida) for those needing individual policies.
There really aren't that much differences between the 3 states - mostly comes down to preference. For us Texas was a no-brainer because we were already living in TX when we retired and started fulltiming, and Escapees is such a great outfit to work with, it is always our first recommendation.
Barb