Choosing forum software based on modifiability

Question

I am aware that this question will be judged as a non-programming question but I would like to point out that my software decision is very largely based on the programming standpoint.

I am interested in changing from SMF to a better forum software. Unfortunately I'm unsure of which software I should choose. Many people like to recommend vBulletin($), PhpBB($0) or SMF($0). In my experience the way the themes are organized in SMF has completely destroyed any possibility of me wanting to work on it. There doesn't seem to be any distinction between the View and the Business logic.

So I'm asking this from a programmers point of view: which forum software provides the most opportunity for modification and straightforward theming without hindering the ability for SEO or other customization?

I realize this may not completely fit within the constraints of a relevant stackoverflow question but I don't think there's anyone better for giving advice about well thought out design.

Answer 1

I've done a bit of phpBB hacking myself and it's not that hard, especially if you're doing something small. I think the software is reasonably well designed. A lot of people have made and released modifications/patches (and themes) for phpBB, some of them representing pretty significant additions.

You can even adjust the color scheme dynamically, from the administrators' control panel, no programming needed.

Answer 2

I ran a phpBB forums for 7 years before switching to vBulletin. I will never go back to phpBB. vBulletin has a great plugin / hook system that allows you to modify any functionality you want without touching the core code, this makes upgrading very easy.

The template system is great also. You have full control over the output on the page.

The vBulletin API is very well documented where phpBB's is very confusing, hard to work with and requires changes to the core code making upgrades and patches a nightmare.

Yes vBulletin costs money, but the dev time you save well offsets the cost of the software.