[quote name='BustaUppa']UMK3 did lack a lot of the aesthetic polish that MKII and the original MK3 had. However UMK3 has by far the most balanced gameplay in the series. That honor could have gone to MK Trilogy, but the overpowering brokenness of Noob Saibot and Rain (and the inclusion of the bosses) spoiled it.[/QUOTE]
Yeah, playable bosses never help to balance out a fighting game. Now I know Noob (and to a lesser extent, Jade) were crazy overpowered, but what was the deal with Rain? I don't remember him being all that popular.
As for MK:A, I'd say pick it up only if you're a fan of MK. Otherwise, grab Deception first. It's a nice jumping in point, has a nice pool of fighters, three minigames that don't suck and most importantly, it's cheaper.