Boy Genius has exclusive numbers on Verizon iPhone sales for the first five days of availability. They're good, but they're not that good, and supposedly Apple and Verizon expected more.
• Thursday: Verizon = 909, AT&T = 539 • Friday: Verizon = 916, AT&T = 680 • Saturday: Verizon = 660, AT&T = 471 • Sunday: Verizon = 796, AT&T = 701 • Monday: Verizon = 711, AT&T = 618
Not dramatically better than AT&T, but not lower either.
The problem is comparing these numbers right now. I'd say a good number of people are waiting for iPhone 5, or are locked into their current contracts, or prefer Verizon stores (or buy them through business channels), or one of a few other scenarios that explains why they can't currently switch to Verizon's iPhone. The real test is going to be looking at sales of the iPhone 5, where the two phones launch simultaneously. [Boy Genius via 9to5Mac]