I currently use Octopress for the http://onthejvm.com blog, and it's been just OK. I've been jealous of all the nice features being included in the latest Jekyll and have been thinking to move over, whenever I have time (i.e. not any time soon). But given the latest announcement of what's coming in Octopress 3.0, I think I'll give it another whirl.
If I'm being harsh, I'll tell you that as it is now, Octopress is basically some guy's Jekyll blog you can fork and modify. The first, and most obvious flaw, is that Octopress is distributed through Git. I want to punch through a wall when I think about users wrestling with merge conflicts from updating their sites. It's absurd.
That's a pretty good way to sum up my experience. I didn't mind the Git-fu, but it was still disconcerting that I had to resolve rebase conflicts in my blog platform.
There will no longer be a division between Octopress and Jekyll.
Looking forward to this bright new future.