Free-Standing Implants To Retain Overdentures?

Larry, a dentist, asks us:

I am hearing more and more about using free-standing implants to retain
overdentures both in the maxilla and mandible. In the mandible, two
dental implants in the canine areas appears to be the most frequent design. In
the maxilla four dental implants in the canine and second premolar areas
appears to be the most frequent design. Bars seem to be on the way out.

My understanding is that bar retained overdentures are really RP4 designs in that they provide most of the support for the overdenture instead of the traditional denture bearing areas. In terms of maximizing chances of success, I think bars are a poor choice unless they have multiple dental implants for support and stability. I think the RP5 design using free- standing dental implants for retention and bearing areas for support provides the best overall treatment plan. What are you all doing? Are Bars in or Out? Thanks for any comments.