I honestly didn’t realize there were so many options.
As we have 5 acres I’m leaning towards an in ground installation in our side yard. We have a flood control dam/pond adjacent to and below our property so I’m not too worried about flooding, but I do like the idea of not being underneath my truck/house if it should collapse.
If you've got the room, put it on the SW side of the house. Most tornados move from the SW to the NE. If one does get your house, you'd be less likely to have debris covering the shelter access. JMO
Best of luck in your decision!