So far, I really like the new 2.7 better than any of the previous versions of WordPress. The navigation moves to the left with slides for picking what to do in each category. Much more easy to use than 2.6. I am even tempted to upgrade while 2.7 is in RC.
I don’t use this blog as much as I do use my personal one at ezrasf.com/wplog. Wordpress.com tends to upgrade these accounts to the new versions while in beta. So it gives me an idea about whether to upgrade or not at my other sites. So I check out this blog before upgrading.