I tend to disagree. I could have gone either route, but chose the corporate route, and got typed after 6 months, in a Westwind.
At most regionals, you are looking at a MINIMUM of 2 years to upgrade. 2 years at a low end carrier at that. At the better carriers, it's probably more like 5 + years to upgrade.
But, on the other hand, corporate is all about who you know. If you don't know anyone with a corporation, you're chances are much more slim. At the regionals, they will interview you now without anyone walking your stuff in.