The American Consumer Satisfaction Index (ASCI) today released its latest results for consumer satisfaction, with Sprint Nextel and Verizon Wireless leading the way among major wireless carriers. T-Mobile USA and AT&T showed significantly lower scores ahead of their proposed merger.

Among the big providers, Verizon Wireless dropped 1 percent for a second straight year, falling to 72 to tie Sprint Nextel, which continues its upward trend, rising 3 percent following consecutive double-digit gains. In just three years, Sprint has emerged from 15 points below even the second worst in the category to claim a share of the industry lead.

In the wake of their proposed merger, AT&T and T-Mobile showed a large deterioration in customer satisfaction and in customer service. T-Mobile fell 4 percent to an ACSI score of 70, matching a five-year low, while AT&T descended by 4 percent to 66, its worst score since 2006, the year before the launch of the iPhone.

“It is common to find a reduction in customer satisfaction after mergers, but it is rare for customer satisfaction to drop ahead of a merger,” said Claes Fornell, founder of the ACSI, in a statement. “Assuming the deal is approved, it remains to be seen if a much larger AT&T can regain the strength of its customer relationships.”

The aggregate of smaller wireless providers, such as TracFone and U.S. Cellular, continues to lead the category, up 1 percent to an ACSI score of 77.

Customer satisfaction with the cell phone devices themselves also dipped slightly, down 1.3 percent to a score of 75, with Motorola gaining 1 percent to a score of 77, outpacing last-place Nokia, which dropped 4 percentage points to a score of 73.

According to the report, overall customer satisfaction with wireless phone service dropped 1.4 percent to an ACSI score of 71, but remains much stronger than it was prior to 2010.