Every time a phone company comes out with a new plan, it has the probability of beating out its competitors current plans. Whatever the schtick is, it will always seem more appealing than whatever AT&T has at the time, regardless of whether or not it actually is. So there is little doubt that Verizon will flourish for as long as their new data plans are new and unmatched. However, as soon as AT&T or any other company for that matter, steps in with something newer or better, Verizon will be kicked back down until their next round of extraordinary ideas.
AT&T has very low-cost data plans available for their customers. They will continue to be less expensive in data prices when compared to Verizon's new plan. When AT&T get wind of the new data costs that Verizon have, they will soon discount their data plan to keep their customers satisfied.
I don't think the release of the new data plans will forge them ahead of AT&T. The coverage area of Verizon is terrible in my opinion. Their customer service is sub par and they lack in that area greatly. With that being said I do not see them going ahead regardless of what they offer.
I think that this new data plan is nothing to write home about. AT&T has many great plans of their own. These two companies are still about equal, and I would pick either one depending on what exactly I was looking for. Verizon's data plans are very similar to ones tried by other companies as well.