Haha you know this is a match I love. My favorite 2 characters against each other...
KITANA
If you don't have IAFs against a good Mileena, you're in big trouble. Most Mileena players do not know what to do against a Kitana that uses IAFs. I like to mix up great caution along with great aggression in this match. Try to time your IAF throws so you at the very least trade projectiles with Mileena- obviously the fan does greater damage. Buffer the IAF raise and make Mileena pay for any jump ins, or whiffed jump-forward air sais. A good play against a spamming Mileena is to keep inching your way forward, and trap her in a corner. She will often try to roll her way out, which sets up your 70% combo fan raise corner combo. Kitana has the better CQC by virtue of her fan swipe. Often time this match comes down to who times their jump kicks and sweeps better. If you don't know IAFs, use the same strategy to try to trap Mileena in a corner. When she jumps at you, anti-air uppercut her. Both women have awesome uppercuts. Square wave when Mileena jumps away or gets spam happy, but be careful that you don't end up landing next to her and getting uppercutted.
MILEENA
She should never lose this match. IMO this is one of the easiest matches to win with Mileena. If you sai spam, you basically shut down any Kitana except the very best. Use your roll sparingly against Kitana- blocking and fan raise combo-ing this is the only way Kitana is really going to do any real damage to you. Use the drop kick even less, doesn't get you very far in this match. Don't be afraid to get aggressive, as her CQC is nearly identical to Kitana's. Though really if you turtle this match, Kitana can't hurt you except with IAF throws.
Hard to say overall. There were times vs InsaneBoss' Mileena that I would beat him 8-2 with Kitana (see video below) in a set of 10. Other times he would 10-0 me- it just depended on who played great that day. Should be a 7-3 match for Mileena though, unless Kitana is really on fire.
@MKillBill- 14 hours, but only because I was at work all day!