I'll take 50fps at PAL resolutions over 60fps at NTSC resolutions any day of the week, so long as the framerate's steady in both cases.
60fps good, 50fps bad is a kneejerk reaction to the abysmal quality of 50fps conversions done by certain large developers in the past. You know who you are.
Personally I won't be getting the PAL version for the reason that Deg brings up - I'd like to have the option of playing it on HDTV when I finally get one.