Hector,
Thanks for the post.
1) I think it's a very good tool, one that I return to at times certainly. Do I think it's optimal? Eh, that'd be a bit strong but it's definitely up there.
2) I stopped using it because it was beating up my shoulders a little too much for my liking. I like L sits/V Sits/Lever work these days. I think those and ab wheel work are probably my favorites for an intermediate-advanced lifter who can do them reasonably well.