I watched Andy Pargh (the gadget guru) test drive a Newell Coach that offers a steerable tag which Newell has produced since 2004. Andy has a whole line of video's on RV's.
I think the advantage of a steerable tag is that the tag can carry the load in tight turns. Most coaches with liftable tags will lift all the way. Ours will partially lift releasing most of the weight on the tag. If I'm not mistaken, the H3 Prevost chassis tag does not lift all the way, the XL Prevost chassis lifts all the way.
Like Roadpilot above, I only lift my tag on tight turns, especially when reversing. I'm curious on a steerable tag if there is more maintenance involved. Do they get out of alignment?, etc.
Safe travels,
MM.