Which one fits best?
You haven't defined what you mean by 'better' either. As far as the safety angle is concerned I think I am right in saying that Giro's are only certified to pass the EN - i.e. the same test. One may be safer than the other, but the tests don't give us that information.
Discounting safety then it just comes down to which helmet has the best venting, looks nice and feels good on your head. So you need to try some on really. Fit is the most important as helmets, like all safety devices, are not very effective if they don't fit properly or if you don't wear it due to it being uncomfortable!
Sorry for the rambling reply. I don't know the exact models myself as I don't wear a helmet, but I dare say they will both do a job.