The way I understand this stuff working is that it stops the sperm from being made, but doesn't affect the (for lack of a better term) seed cells. It should be safe (allowing for a recovery time much like the female pill has one for women who go off it.)
That said, I'm all for this. One night stands and whatnot where diseases are the first concern, obviously a condom is best, but why not double up on your protection?
For committed relationships (A place where condoms are less a worry for many), having both partners using protection is a good thing as well. If something happens to one, the other's protection still holds. Also, as misogynistic as this will sound, I like this idea for the simple reason that it's protection for the man himself. I know (if you accept 2nd hand acquaintances as 'know') two girls who went off birth control in secret because they thought their boyfriends were losing interest and wanted to keep them by getting pregnant.
Personally, I can't see much of a downside to using the pill and a lot of plusses.