Whatever Intego's behavior might have been in the past, they seem pretty honest these days. Ironically, just today there's a story on the MacWorld site crying wolf about a "trojan" called Tsunami, based on a Sophos report that also calls it a trojan. But it's not a trojan, it's just a hacker tool that would have to be manually installed to do any harm, and Intego is the only company so far (from what I've read) that points that out clearly, adding that any risk is very low. Seems like pretty honest behavior, considering they could have talked it up like everyone else and used that to sell their software.
Of course, that does not say anything about the merits of their software. I've seen people with frequent kernel panics where the panic reports implicated VirusBarrier, and removing VB was an instant cure. So, while it may work fine for many, there are potential dangers involved with using it.