For those that do not know what PHP suEXEC is:
It is a php module, the does away with the apache user 'nobody',
it also does away with permissions 777 and 666, meaning files and folders can not be writable by others/the world, only the account owner.
And since there is no user 'nobody', emails sent from forms on your site can be traced to the account username, this helps cut down spam.
I think its a great feature for security, and helps track down people abusing email forms.