Well, that was the topic for this week's UC Strategies podcast, and if anyone should have qualified opinions, it's this group. Everyone has their own take on this, and the podcast is a great listen. I provided the opening comments, and there was lots of back and forth on the utility of a PBX. However, we're all pretty much of the same mind that the PBX as we know it is simply out of kilter with how the communications landscape is evolving.
You can access the podcast here, and while you're on the site, there's a nice related article from Dave Michels that you'll enjoy too.