I should note that reducing noise is not my concern. I've always used screws and without issue re: noise, but they can be a pain to install, scratch the case and chew up the fan housing a bit. The rubber/plastic mounting seems like it would address some that, including ease of installation.
Anyway, i'm doing some fan related mods to my case and will be ordering some 120mm grills, so i'll need to order some additional mounting hardware at the same time. I was just curious if there were any perceived advantages in using something other then screws.