Depends on your budget and current lens collection.
If you can afford the $2000 difference, then sure. If not...and you're stuck with less-than-stellar glass, I wouldn't. I don't care how high you can crank the ISO, it's always better to shoot at the lowest ISO possible. Just like all other camera-photo-threads on POTN, there have been some stunning photos posted by new 5D3 owners. And there have been many point-n-shoot snapshots posted by other 5D3 owners as well.
Don't get me wrong. The 5D3 is a nice camera. But $3500 can get you a 7D and 70-200/2.8ii. I'd go for the latter.


