I wanted some additional features over instawallet - such as mobile usage (easywallet.org is very quick and fast to use with iPhone with QR code scanning), and more anonymity (new addresses generated automatically each time one is used).
FYI Instawallet actually has a full-fledged iPhone app, it's called FriendlyPay, Android one is on its way, and it doesn't take fees on outgoing transactions. Instawallet now also has a nice websocket API that will push balance updates in real-time without relying on long-polling.
The android app is now available (search "instawallet" in Google Play applications)
