If you have multiple email accounts which you use on a regular basis, like me, managing those accounts can be a right pain. The built-in mail client on the iPhone does do the job, but Sparrow does it better, and with style.
Sparrow supports all IMAP accounts, which are Gmail, iCloud, MobileMe, AOL, Yahoo and any other IMAP account you might have. Hotmail and MSN won't work, just warning you before you pull the trigger on buying the app.
Like many of the latest apps, Sparrow has also adopted the swipe to next/previous screen feature. There are layers, starting from the list of account, all the way to the email list, these are the layers you can simply swipe through.
A feature I love most is the ability to swipe on an email, when looking at a list. When you have swiped on an email, you reveal reply, favourite, label, archive or delete options - a very quick way to sort emails and reply to them.
Other features include a unified inbox, portrait pictures added to emails, can mark all emails as read, thread view and a priority inbox feature - just like the one out of Gmail. You can tap on the bar at the top to switch through inbox, unread and starred. There is a universal search bar, which enables you to search everything, or search a specific label, inbox..etc.
The app is absolutely beautiful and silky smooth when it comes to use. You can switch through emails super fast and the animations are super slick. The design is kept as minimal as possible so you can concentrate on the actual emails.
There is one massive downfall with this version so far, it doesn't do push - well not yet anyway. Which isn't great for anyone who needs to keep up with the emails instantly. This can either be a make or break feature, so it's completely up to you whether it becomes your primary mail client.
Hopefully the devs will bring out push support soon. It will be a no-brainer then.