(Sparrow’s interface, which has attracted a lot of favorable comment here, seems deliberately modeled on Apple’s e-mail webpage on its iCloud site.) Why use it rather than Apple Mail? As an e-mail client, its two strengths are its ability to handle g-Mail, and the fact that it allows Mac users who can’t or won’t upgrade beyond Snow Leopard to access iCloud e-mail, as long as they have already set up an iCloud account (such users will probably want to have a look at BusyCal, which does the same thing for calendars, albeit it’s a little on the expensive side -- apparently there’s no similar solution available for contacts, although you can use Address Book as a front end for contacts in a g-Mail account). When MobileMe shuts down, this will be a real boon for owners of older Macs and people who still rely on Rosetta-accessed software. Sparrow has a “Mark as Spam“ option and imports the Apple “Junk” mailbox l, but as nearly as I can tell it doesn’t have any spam filtration system and isn’t “teachable”like Apple Mail. Personally, I don’tsee much value in sending attachments via Dropbox or iCloud, but this is probably some failure of my imagination. There is only one seriously objectionable feature: like Apple Mail, it interacts with the Address Book database and has an auto-fill feature. But it interacts a little too well -- where I work we exchange fairly sensitive confidential documents by e-mail and sometimes some bozo (once or twice I myself have been the bozo in question) sends something to the wrong addressee because he isn’t paying sufficient attention to what the autofill is doing, so John Jones gets it rather than John Smith. When I caught on to this danger, I turned off that feature in Apple Mail. I don’t see any way to switch it off in Sparrow, and this is a bit scary. If you are in a position where you run a similar risk you would probably do well to look elsewhere for your e-mail client.