is there a difference between the pal and ntsc versions?

FPS, probably. (PAL being 50 and NTSC being 60), as is usually the case with games on region-locked consoles.

If I'm not mistaken, on PAL you're forced to select 50hz vs 60hz on boot-up, which makes for slower resets and therefore worse reset efficiency. I also noticed that the order of the TMs in the mart in the under is different. Hidden Power (TM10) is at the top of the TMs on PAL, while at the very bottom on NTSC-U.

PAL: NTSC-U:

(Screenshots are from my PB//PAL vs Exarion's PB//NTSC-U)