I was first a bit skeptical, but after being out in the field and getting used to the endless possibilities of tilting and shifting the focus plane I can't do without it.
Landscape and architecture get a new meaning, but also portraits/wedding can get that nice addition if you use the TS intelligently.
Perfectly sharp (sharper than the corresponding prime, IMHO) the superiority is easily visible on my 5D mkii.
Not having an auto focus (no, I am not complaining), I would suggest also to add a manual diaphragm control for quicker control.