Buggy. Slow.
Mail shows 1 Unread message in the "Folder" navigation pane on the left, but in the "Message List" window, I cannot find an unread message. I used the "Filter" to show "Unread" only, and the message showed up, but then when I turn the filter off, I can no longer see/find the new mail. I tried repeatedly to find the message without having to use the "Unread" filter, but nope - couldn't be done.
My next step was to hit "Refresh" on my (fully updated) Chrome browser. Lo and behold - the previously hidden unread message appeared right where it should have been in the "Message List" window.
Y'all got problems with this new, super-slow, clunky, inconsistent interface. (I'll give you this tho - it's better than that last horrific iteration, which thankfully you let me avoid using.)