You no longer have to worry about which version of Mega Man: The Wily Wars will be bundled with the Sega Genisis Mini. A Sega PR representative has confirmed to The Mega Man Network that it will be the NTSC version, which runs at a smooth 60Hz. Thank goodness.
For the uninitiated, the PAL version of The Wily Wars ran at 50Hz. This version is noticeably slower than its NTSC counterpart in practically every regard: sprite animation, music, speed, etc. Here's what the PAL version looks like and here's the 60Hz NTSC version. It shouldn't too hard to see which one is superior.
The video embedded at the top of this post purportedly features footage of The Wily Wars running on actual Genesis/Mega Drive Mini hardware. Indeed, it's the NTSC version. For me, this just went from an "instant buy" to an "instant instant buy". Can't wait!
Source: The Mega Man Network