I don't believe I've ever heard anyone be critical of the R. Taylor peghead, yet the two are virtually identical...
I don't love the shape in either case, but in context, I don't mind the R.Taylor look because it's supposed to be a different brand and seems to suit the GS and GC shapes nicely (I don't like the R.Taylor headstock as much on the DN).
As for the SB, I think the regular Taylor headstock would look better on the single cutaway models. Just a matter of preference. That said, I think the tapered "R.Taylor" style headstock is a better fit for the double cutaway than a normal Taylor headstock would be.
I'm just glad they kept the normal Taylor headstock on the T3, because if I ever get a Taylor electric, that's what I'd pick. Now if they weren't so darn expensive...
Not that it's unheard of for a company to use different headstock styles -- a pretty famous electric guitar company comes to mind...