Today marks the launch of the Verizon iPhone 4, and the end of a nice little honeymoon for AT&T. For the past three years, the iPhone was only widely available on AT&T's network, but with the debut of the Verizon phone, customers will be able to choose between carriers.

Early reviews indicate that Verizon's giving AT&T a run for its money, though most everyone agrees that the Verizon iPhone is far from perfect. It's slower to download data, it can't do data and voice simultaneously, and a lot of people have problems with Verizon's unpredictable policies.

Still, tech-heads have been looking forward to the Verizon iPhone for a while now. So when stores opened their doors this morning, why weren't the lines longer? Dan Frommer at Business Insider points out that in many places, instead of customers trampling each other to be the first to grab a Verizon phone, there were only a handful of people, or none at all.

But Verizon shareholders take heart: an absence of huge crowds doesn't mean an absence of sales. "Many if not most existing Verizon customers already bought the phone through online reservations and led to the carrier's best-ever first day sales just by themselves," notes a post at Electronista. "Early adopters have the option of getting the phone at Best Buy and Walmart today as well, where past launches have often removed one or both of these chains as options." Plus there's also the fact that, you know, it's February, and you have to really want this phone to stand around on a sidewalk before the sun is up.

Speaking of cold, it's possible that no one's happier about the Verizon iPhone than Apple fans in Montana, Wyoming, North Dakota, and South Dakota, all states where AT&T coverage sucks. In Rapid City, South Dakota, Verizon store employees have been preparing for an onslaught. Stores in Billings, Montana and Fargo, North Dakota saw early-morning crowds today.

Meanwhile, the coming of the Verizon iPhone obviously isn't great news for AT&T. A story in Reuters quotes Jim Liu, an iPhone user who can't wait to break his contract with AT&T and switch to Verizon. According to the Reuters piece, "analysts expect some AT&T customers, like Liu, to leave for Verizon due to AT&T's patchy reputation, particularly in cities like New York and San Francisco."

Taking a step back, though, Eddie Yoon at Harvard Business Review argues that AT&T shouldn't panic about shedding a few fickle customers. This is actually a great opportunity, he says. "Smart companies need to routinely rid themselves of less profitable customers," Yoon writes. "If you can precisely value your consumer portfolio, then sometimes a little bit of losing can lead to a lot of winning."

AT&T did, in fact, announce today that anyone with an unlimited messaging plan and a qualifying voice plan can make free mobile-to-mobile calls, no matter what network they're calling to. Will it be enough to offset the nine million iPhones Verizon is expected to sell this year? Probably not--but it does suggest AT&T isn't planning to let the new kid come and take over everything.