Hi.
I have used many bulletin boards before and some have been good. But none have come with the amount of features and help that vBulletin has. Not to mention the 1000's of hacks that will turn your vBulletin into something so good it far outweighs the "free" boards. Best board on the market IMO
As for a portal system, take a look at
www.teckwizards.com It's called vbhome (lite), it's easy to install, easy to use and manage and IMO is far better than any other currently out.
Hope this helps.