Actually in the process of switching from vbulletin to mybb.
Even though its supposed to be community software... Vbulletin's "community" especially support is poor.
As soon as i started looking at mybb, i had a read at the website, asked a few questions on the forum about converting, got great, helpful responses and a link to where i should go, all for the cost of nothing.
No harassing me about my license code, if i paid to have the branding removed, "look it up noob" or general nastiness... with a pricetag.
It may be elegant to have a paid solution but i'd rather innovation, speed and community support any day.
Best of luck with what you choose, because months down the line its a pain to change lol, you cantgo wrong with any of the earlier suggestions though.