Subscribers in large markets such as San Francisco and New York City have long complained of lackluster 3G service -- though analysts were somewhat surprised to see AT&T ranked last in 17 other cities.  In San Francisco, Verizon had a 74 overall score, with AT&T receiving a disappointing score of 39.

Prior to this report, many tech enthusiasts believed AT&T struggled in markets where consumers demand the most of their providers, but that turned out to be incorrect.

"We believe it has been an elitist investor view that only a few high profile AT&T markets are having problems on the theory that only 'tech savvy' residents of coastal cities would find enough use in the (Apple) iPhone to impact the quality of AT&T's network," said Walter Pieck, a Pali analyst, in an investor note.

There has been an increased amount of chatter regarding the iPhone switching to Verizon Wireless (after a network switch from CDMA to LTE), which leads the way among subscribers, after the AT&T/iPhone exclusivity contract ends.

AT&T must now attempt to fix its customer relations issues -- especially if it wants to keep the iPhone -- as a combination of dropped calls, poor 3G coverage, and similar issues. If Verizon doesn't get the iPhone, it's possible T-Mobile, which ranked No. 2 behind Verizon, may be the next company to offer the iPhone.

AT&T responded with the following statement to Consumer Reports:  “We appreciate and value all customer feedback. We learn from it and it helps us serve our customers better. Without question the surest indication of customer satisfaction is churn, or turnover. For the last quarter, our postpaid churn was just 1.17 percent.”

Consumer Reports latest findings seemingly add more fuel to the fireballs that Verizon has been throwing AT&T's way over the past few months.