They all fit VERY differently, so you had better get out and try them on. It doesn't matter what ANY of us say about a helmet if it doesn't fit your noggin.
All three are quality items, and you can't go wrong with any of them. Yes, Shoei's are notorious for fogging up. But AGV's are notorious for having quirky fit. Neither of them fit my head worth a shit, so I never even considered actually buying them.
The Suomy fit my head pretty well, but not quite as well as my Arai Quantum... and it was more money, so I just went with another Arai.
If none of the helmets you mentioned fit you, try the Arai. The only complaint most people have with Arai is the price and the noise. They ARE some of the noisiest helmets you can get.
Also consider the Shark RSR... another VERY nice helmet if it fits your noggin.
When trying them on, be sure to wear them for a pretty decent amount of time... and try on a few of the same size for each of the models, as the fit can vary slightly.