EW YORK (CNNMoney.com) -- Sprint Nextel has been maligned in the past for poor customer service and network quality, but new evidence shows that the nation's No. 3 wireless company's improvement efforts are starting to succeed.

According to recent third-party studies, Sprint's (S, Fortune 500) network quality is improving faster than its competitors, its 3G network is the most reliable and it has the best 3G signal strength in the nation's major metropolitan areas. Sprint is also the only wireless provider that has an up-and-running 4G network, and its rates are mostly favorable to its biggest rivals, Verizon Wireless (VZ, Fortune 500) and AT&T (T, Fortune 500).