For anyone interested in learning the game, here is the ranking of versions at the moment.
Tier 1: Japanese. Japanese is conditionally the fastest version of the game; if at any point you need to soft-reset the game, the title screen takes about a second shorter to load. This matters for any deaths as well as for any soft resets on glitches.
Tier 2: Korean and European. These versions will equal Japanese if you never have to soft reset during the run. For speed purposes, any of these are fine. Run by preference/availability.
Tier 3: North American and Australian. This version is the notoriously inflated one, where enemies have considerably more health (up to 1800 between EPS Phase 2 on NA vs other versions), and things cost more. The former is the big point against it at the moment, there are a few version exclusive glitches but the run is considerably lengthier due to boss fights.
Worth noting, we run on DS/3DS hardware as the WiiU virtual console is harder to region-break, has worse buttons for mashing, and the timing for things is different, laggier and less consistent. Functionally, there is no advantage to 3DS over DS, though some runners find it easier to mash on 3DS hardware.