Well, u could have added the question to the ArmA2 forums.
I doubt you find a site with more missions than here, and probably other "big" sites will have the same we have (and of course less than here). U can find different ones though (not sure how many if any).
Many good missions i guess are not released in sites like ours and the official forums and are kept "private" in clan/community servers. Try to join them to get the missions.
Doh... did I post this in the A1 forum.... sorry man :S
Yeah I have searched many A2 sites but none seem to come close to ArmAholic in terms of downloadable content (mods, addons, missions etc...) Thx for ya relpy and cheers big ears :P