What? You mean you don't think Kreia is Kae, or do?
Anyway, though Kreia was smarter, I'd have to say Malak. Kreia was a failure at everything she did. She failed as LS and DS, she failed training Revan, Sion, and Nihilus, and depending on what you did in K2, she failed at training the exile. She couldn't do anything on her own, either. She needed the exile to do all her dirty work. Heck, she couldn't even stand up to Nihilus. She was incredibly weak (story-wise) until the end, in which she was stronger than she really should have been. And finally, she failed at killing the force. I know it's cookie-cutter, but Malak's motives in K1 were a whole lot better and realistic than Kreia's motives in K2. The only thing Kreia had going for herself was her manipulation and intelligence, though I do think she was more evil than Malak was.