You can optimize any of them. vBulletin ($160 USD) and Simple Machines (open source, free) are best for SEO "out of the box" without additional optimization, although they too can be improved. phpBB is not very good "out of the box" but benefits enormously from the Able2Know SEO mod.
I dont know about mods for phpBB to optimize it, but I do know that it is the worst forum out of the box as far as SEO goes...
Does well out of the box. Can be improved with a bit of tweaking. Overpriced. Overkill. Save your money and buy a backup hard drive or something.
Learn to do it yourself and you'll be an expanding product getting better And you'll have saved $150.
I too agree that vBSEO is overpriced. It might be an expanding product, but why spend the money now if it is not currently worth the money? I'll wait for it to actually be worth the $150 before I buy it with the hopes of getting my money's worth a year from now.
it's overpriced, but it's not a bad product. i bought it and use it because i like the features it's has and it's ease of use.