I would love the PortaBote if they were fast, stable, light and easily deployable. Of course, they're slow, unstable, heavy and a PITA. But other than that, they're great.
We're sold on RIBs. We've had a number of different kinds of dinks, and while nothing is 100% perfect for every situation, the RIB does the most things the best. And even as to those things for which it is not "best," it's damn good.
Aluminum v. glass. AB v. Achillies v. Caribe v. Zodiac. 10' v. 11', etc., I could be swayed. But for us, a RIB it is.
He does have a good point there, especially if you're planning on cruising long-term and long-distances... fiberglass is something you could carry the materials and patch yourself in a pinch... can't do the same as easily with aluminum.
Personally, I'd go for a PortaBote instead... it stows a lot smaller, and they're a lot more durable, since they have no inflatable portion to damage.