The 4 is miles better than the 3, I've spent a year with each. The battery life alone makes it worth the extra, the 3 is shocking.
Bear in mind the 5 (or 4S if they decide to call it that) will be out in the very near future, although there is no confirmed date yet.
2012 Alpine White E92 335d M Sport LCI | Coral Red Dakota Leather | Media Package - BMW Professional | 313 Wheels | Evolved |
Previously - 2009 Alpine White 325d M Sport LCI | Auto + Paddles | Media Package - BMW Professional | BMW Performance Front, Sideskirts and 313P Wheels | Black Grilles |
Carbon Black E46 ///M3 '04 | Manual | Evolved |