The app now supports general IMAP, so for those of you who were waiting to add Yahoo!, AOL or MobileMe accounts to Sparrow and totally ditch Mail.app, you can now do so. For the many Mac users who use the app to access your Gmail accounts, Priority Inbox is now integrated into the app.
My personal favorite new feature is a dedicated view for browsing your unread email. Simply choosing "unread" from a tiny pop-up at the top of the inbox displays only your unread messages. There's also an unobtrusive formatting bar for messages, so you're free to change the font, style, size, color, alignment and indention, or even add a bullet list in the compose window.
One thing that made me surprisingly happy was the new three finger swipe multi-touch gesture for showing or hiding the preview pane. On an 11.6" MacBook Air, it's nice to be able to minimize the real estate taken up by the Sparrow window.
If you've created contact groups in the Mac OS X Address Book, Sparrow 1.1 now supports using those groups for doing mass mailings to a team. The Sparrow team also fixed a long list of bugs in the initial versions, improved sync with Address Book, and added improvements to the mail database, scroll performance and memory use. The update takes little or no time to install through the Mac App Store, and for existing Sparrow users, it's a solid and welcome update.