Compared to the NTSC-U version, you have more ammo for the Amun Bomb (hand grenade) and Cobra staff weapons.
Considering both can be used to perform bigger jumps and to sequence break, it can be useful.
Also the voices are in Jap.
The PAL version is the one with the most differences. It doesn't have the extra ammo of the NTSC-J version despite being released later. It's optimized to run at the intended speed in 50hz, but there are some timing differences: the firing rate of the pistol and M-60 are lower, and the shots of the Mummy enemies are faster. Also there are a lot less HP/AMMO refill items to be found in levels, one level has a small extra area, and there are 2 new glitches exclusive to that version (the underwater mines make the kamel sound, and the kamel at the entrance of level Canyon of Chaos is tagged as an exit Kamel meaning you can skip the entire level).
So the PAL version is the fastest, that's what I used for my speedrun, but it's also the hardest