I experienced some "buggy" things on Chrome when using yahoo mail. Like when I have opened a mail it does not change its color to being already read. It doesn't happen to me on Firefox. And sometimes when I already deleted a number of messages on my Inbox, when I open yahoo again the next time the deleted messages are there again!
Though I really like Chrome, especially the ability to enter search strings on the address bar is so cool. But IMO Firefox is way off more stable for now.