For those who might have missed it, KOF Maximum Impact Regulation A is an upgrade to last year's KOF Maximum Impact 2. This is also the first Maximum Impact game to be released in arcades; the game came out a few weeks ago, and has quickly been released for the Playstation 2 as well.
The PS2 version appears to be a straight-up arcade port with a few added modes. The main menu has Time Attack (the main game), Versus, Practice, Network Battle (restricted to Japan only and is a pay service from KDDI), Options, and a Jukebox mode where you can check out voice and music samples. That's it. No challenge mode or story mode is present. The match structure has been changed to resemble the older KOF 3-on-3 team style (which you could already do in the previous MI games' versus mode anyway). I haven't tried versus yet, but time attack is strictly team battle only.
Like the arcade version, all of the characters are available from the start, and have four outfit colors per regular/alternate versions. The graphics are basically the same as Maximum Impact 2, although most of the females seem to be noticeably bouncier and their undergarments have been made thinner (I.E. thongs for more fan service). I would have preferred more outfits to this.

The entire cast from MI2, minus Armor Ralf, is back, joined by Ash Crimson, Blue Mary, Makoto Mizoguchi (from Data East's Fighter's History series), and newcomer Xiao Lon, who is a bit like a female version of Duo Lon. She has a kiss super move that's also going to be popular among fanboys, and while on the subject, I have to add that Ash's alternate outift rivals Hanzo's as one of the worst design choices ever made.
Characters have been tweaked to make the game more balanced, although against the CPU, I was still getting destroyed by Seth and Billy/Lilly Kane. New moves have been added as well; I need to play more before I can really say what the major changes have been, but everything that's been added is definitely welcome.
There's one new background (for Mizoguchi, I think), plus new alternate versions of the older stages. Some have new music; I noticed that the alternate version of the Kyokugenryu Dojo plays stage music from Sengoku 3.
So is this game worth it? If you liked MI2, it's definitely worth getting and plays even better than before. However, if you only played MI2 for the single player (since it was quite lengthy if you add in the challenge mode), there's nothing here for you; this game is made with strictly with multiplayer in mind. I'm using the game as practice for the arcade version.
I haven't beaten the game yet (a team of Lily, Seth, and Xiao Lon owned me several times), but hopefully more features or modes can be unlocked. I'm not holding my breath though.
I plan on taking screengrabs a bit later on, if anyone's interested, but I don't know if anyone even cares about this on Evilbore. :'(