The Skinny: It's the Soul Calibur you know and love, now with even more Star Wars cross-branding!
The Good: The best part of SCIV is the character customization, which allows you to take any of the game's existing characters (except the Star Wars fighters) and redeploy them with different armors, outfits, and weapons. While a Mission mode no longer exists, there is a Tower of Souls mode in which, by either ascending or descending against waves of enemies you can unlock additional goodies.
The Bad: While Darth Vader (PS3 exclusive) and his Apprentice (from the Force Unleashed game) feel right at home in the SCIV universe, Yoda (Xbox 360 exclusive), frankly, sucks as bad as the prequels (a tiny guy who can't be thrown makes for a boring adversary). Also, the story mode is only five matches deep for each of the 30 selectable fighters. While that's well over 150 storyline twists, most of them overlap and feel more like an afterthought.
Cheat Like a Champ: The Apprentice is by far the hardest opponent in the game. To easily beat him, hold your block button until he attacks and then quickly grab and throw him. Repeat until dead.
Buy, Rent, or Disembowel? Buy the PS3 version. Or, buy the 360 version and hope there's a game update that turns Yoda into Darth Maul or something.