I had Serendipity 6.3, but it was draining power so badly. I tried every trick in the book to fix it. I was going to go to Cog 4.3, but people have said it had all sorts of 'sleep death' issues. Anyway, nothing seemed to work so I went to stock 2.2. My power drain went away. Problem is I'm so used to the custom roms, that I've had to hack away at it (XDA Forums is my friend) to try to fix it the way I'd like. =(. I really liked Serendipity as well.