Comfortable, ventilated, protects you from unexpected balls.
When you are wearing a neck protector, you'll feel weird, maybe claustrophobic or having the feeling that you are being strangled. But, if you keep wearing it during after afternoon of playing, you won't even know it's there. You may find it a little bit sweaty when it's hot.
In conclusion, for people who are not used to it, it will feel strange, but keep wearing it, keep faith, I personnally like the Redz neck guard better than the Brasseagle one. Expensive for Canadian players. I recommend it to people who like good protection.