The phone is a lot slimmer than its iPhone competitor and features a subtle arc on the back cover, for which the phone takes its name from. It is also very light for its size. Despite this, the phone features a large 4.2" touch screen which uses the same Bravia technology as Sony HDTV's. Importantly for me, it boasts a great 8MP camera, although it does lack a dedicated flash like my old Sony Ericsson C905 had. The built-in LED seems to work well though, but isn't a replacement.
I'm also loving the Android OS and the quality of the available applications on the Android Market. Most of the free ones are better than the paid apps on the C905! Got some great apps to personalise my Arc including GO Launcher, K-9 Mail, SwiftKey X and my favourite mobiles game Peggle!