Sure, anything is possible if you have the money.  I can get 5 more servers to support everything you could ever want and I would load VBulletin (an excellent application) but who's going to pay for that?  ezboard has kept their costs low by adding tons of features but having a slow and unsecure environment... please know there are always tradeoffs.
annbal, you are spot on!   SMF is a great application and is pretty close to PunBB in philosophy.  SMF does have more bells / whistles built in and  I was actually close to migrating over a few years ago, but there were some items that were just deal breakers for me.  If I had a site that was really big and could pay for itself and the resources required I'd go from punBB to VBulletin... but even that application has issues being as big and popular as it is.
DLH, let's leave it at this:  I do this stuff for a living and have MANY years experience and tons of very happy clients and partners.  I value feedback, but when it comes to how to run the backend, I haven't found anybody on the forum that has as much experience as I have (if I'm wrong, I'd love to get an email from those people).