I have an oval head, and find that Bell has always been a good fit. Actually I guess I'm just loyal to them, having used Bell since the 60's on both bikes and motorcycles. Believe they were one of the first companies to come out with bike helmets. So I'd say they are among the leading brands, but I couldn't really say they are "better" than Giro.
As dabac said, it really doesn't matter. No one I know is going to notice or care about the brand name on my helmet.
Aren't Bell & Giro owned by the same company?
As stated by others, they protect the noggin.
I go for looks and which helmet provides the most air flow because I don't like to be too hot at all. I purchased the Giro Aeon because it looks good and provides good airflow.
You sure must be particular about looks since a Bell costs about half of what a Giro does last time I bought a helmet.
No different than how riders are particular about their cycling clothes and specific shoes.
I did say I want the helmet that "...provides the most air flow..." The Aeon meets my requirements at a cost that I am comfortable with. Also, I did not pay regular price for the Aeon.
One could make the same comment about anything - bikes, wheels, components set, cars, motorcycles etc.
When was the last time you purchased a helmet.
...Exactly WHY would you be as picky about your helmet as your shoes? The one looks the way you want a helmet to look while the other can cause almost crippling pain on a long ride if it isn't the correct shape for your foot.