Approximately 26 percent of Apple iPhone users currently on AT&T plan to switch to a Verizon iPhone, according to Thursday data from ChangeWave.

Of the 4,050 people polled by ChangeWave days before the Tuesday announcement, 10 percent said they would switch providers in the next 90 days. About 16 percent of all AT&T subscribers said they will purchase a Verizon iPhone. Among those AT&T users who already have an iPhone, 26 percent will ditch the AT&T version for one from Verizon.

About 41 percent of all AT&T users will make the switch in the next three months, while another 31 percent will do so in the next year.

Among other providers, about 15 percent of T-Mobile users will switch to Verizon for the iPhone, 10 percent of Sprint users will do the same, while 4 percent of existing Verizon customers will switch from their current handset to an iPhone.

ChangeWave said these numbers represent the worst ever churn rate for AT&T that it has ever recorded. The main reason AT&T customers cited for switching providers is poor reception or coverage, at 42 percent. Another 27 percent said dropped calls, while 17 percent said cost.

ChangeWave, however, said AT&T has actually made improvements in its dropped call history.

"While AT&T continues to struggle in this very important area and trails Verizon by a wide margin, it has made significant advances since our previous survey – improving from its all-time worst 6.0 percent rating last September to 4.7 percent in the current survey," ChangeWave said. "The findings suggest AT&T is now taking concrete steps to try to improve long-standing service issues. But can it do so quickly enough to forestall large-scale defections to Verizon?"

Time will tell if consumers ditch AT&T and flock to Verizon's version of the iPhone, but if anything else, the Verizon iPhone deal represents a turning point in the smartphone market, according to Thursday data from comScore.

"The iPhone Verizon deal will no doubt bring even greater competition to the smartphone arena throughout the coming year as Android, iPhone and RIM jockey for the leadership position," Sarah Radwanick, comScore's marketing communications manager, wrote in a blog post.

Radwanick pointed to Verizon's smartphone share, which grew 4 percent in the last year to 27 percent. Though that's less than AT&T's 38 percent market share, AT&T dropped 7 percent last year as more and more smartphones hit the market. Verizon, specifically, benefited from the strong Android-based devices it added to its lineup.

In overall mobile device market share, Verizon dominates with 31 percent to AT&T's 27 percent.

ComScore suggested that any iPhone customers Verizon does manage to nab will likely be in customer segments that are attractive to mobile providers - younger users from higher income brackets. In addition, iPhone users are typically loyal to the Apple brand. More than half have subscribed via AT&T for more than three years, while about 28 percent have had subscriptions for one to three years.

"Although it's too early to tell exactly how consumers will react to the Verizon iPhone announcement, it is fair to say that this deal represents a potentially significant turning point in the ascendance of the smartphone market," Radwanick concluded. "Only time will tell which carriers and platforms will emerge as the market leaders, but it's clear that right now the consumers are winners as they gain yet another option when making their smartphone choice."

For more details, see PCMag's hands on with the Verizon iPhone and the slideshow below.