Well; The topic title says it all.
I plan to use SMF, but I'm determining if I should use PHPBB3; because of the additional features. I love how CleanTalk can be implmented into any site for Spam Protection anyways; But I also know SMF has more free templates; I truly like both since each has their own perspective of features.
I love the features of PHPBB3; but i always stuck with SMF because of the amount of Mods you can use with it; and its easier to install them too!
But what are you're suggestions for templates between the two?
PhpBB3 is an excellent CMS for larger Forums. SMF is probably good for smaller and more simple Forums. Most people these days however are using myBB. Good however you're supporting phpBB3 - I think both are equally good. In my experience however phpBB3 quality of support in their support forum is better and more solid by experts than the support in the myBB community forum. The phpBB3 community forum is also better managed.