Obviously, I like them. Favorite pressing exercise actually... I prefer them over HSPUs and such
I wish I could grab a DB between my legs.. that would be much easier, but they don't make DBs heavy enough (well, they do but not common) and my legs couldn't handle it
Both rings and bars are fine. Actually though at higher weights, the rings become like bars. I don't know if any of you have done a bodyweight ring dip, but it only requires a small bit of stabilization compared to just holding your bodyweight up. Movement of the rings outward away from the body requires increasing the ring height relative to the ground which gravity doesn't like.