There is currently another member on here selling his vbulletin 3.8..
Should I do the switch?
My forum is mahoganyfolk.com (see sig)... is it worth it?
I already posted a lot of my thoughts relating to this here. But long story short, vBulletin sucks in my opinion, and I think you're already doing great. You should get the license and resell it. 😉
This isn't something we can decide for you. If you like MyBB, have good experience with it, and your community is working well with MyBB, then there is no reason to move. Obviously you won't know if vB will work or not until you try it, but I reckon you should hold for now, until you develop a strong userbase.
The question, jglover4168, is what exactly does vBulletin have that MyBB does not which makes you want to convert your forum? Is it really urgent for the life of your forum? Is it important to, for example, gain more attention from users? If the answer is yes, then you can probably start to ask about the price of that vB license on sale. If not, the conversion will not be effective and you will only waste your money.
I've been working with both MyBB and vB longest in my online life, and in my opinion both are great software. One free, one paid. Each with their features and limitations. Depends on what your community needs. I'm more towards the free one, since MyBB is great for a free software, but if you think vB is what you need then go for it.
Based on what I can see from viewing your community for a short amount of time, it's doing well and I don't think converting to vBulletin will really benefit you at all. If I were you I would use the money to invest in some advertising along with some cool new features / plugins if you're unable to code them yourself. 😛