I use (and have used) hierarchical navigation as my primary means to navigate and get around quickly. It is a critical component of my normal usage of OSX and before that OS9, etc. Over the years I have used many of the systems out there, FruitMenu, Butler, PiDock, ittec...

At the change over to my Macintel machine I switched from MaxMenus to Butler because MaxMenus wasn't universal at that time. (MaxMenus has been universal for a while but I only just switched back recently.) (I switched back to MaxMenus since there were occasional times when Butler would crash and I would need to restart it.)

Anyway since switching back again to MaxMenus again, I can really notice the speed differences. Now menus are just snappier and quicker, and the stability is excellent.

In my opinion, MaxMenus in its current incarnation is the best hierarchical navigation tool / extension available.