The only problem that I have seen with running suexec is that it does affect alot of php scripts causing alot of 500 internal service errors pages. It can be very tricky sometimes to make get the php scripts to function with the suexec.
Instead;
mail("$to", "$subject", "$message", "From: $from\nX-Mailer: PHP/ . $phpversion()", "-f $from");
Notice the -f... that is the from address, by adding this at the end of the mail function you can bypass the nobody without using phpsuexec..
;)
