Was wondering if Dolphin is more or less compatibility with games from NTSC or PAL. Does it happen often that some game work with the NTSC but not the PAL version ? Is there any cons in using PAL games instead of NTSC versions ?
Compatibility is rarely different between regions, but generally the PAL versions are slightly more likely to be broken. Also, NTSC TVs run at 60 Hz, while PAL TVs can either run at 50 or 60 Hz, and most games either support both or only support 50 Hz; you can force most games to run at 60 Hz by checking Config > Wii > "Use EuRGB60 Mode" for Wii games (all of them?) or by holding B at startup for GameGube games that natively support both (it's also probably worth checking Graphics > Advanced > "Progressive Scan", but I'm not sure if it'll do anything). For games that don't support 60 Hz, you're probably out of luck unless you patch the game or use an AR cheat.
I recommend playing whichever version matches your region; if you're in the Americas, play NTSC games, if you're in Europe/Oceania, play PAL games, if you're in Japan, play NTSC-J, and if you're somewhere else you should choose between NTSC and PAL depending on what language(s) you speak.
Yes, a very good answer there by
pauldacheez
I'd also add that the NTSC-U games are
minutely more compatible because the NTSC-U region gets tested most by the devs, followed by PAL and lastly NTSC-J. The other regions like Korea get the least amount of testing and games with problems in these regions can take a while to fix.