Computer World decided to trial the three major 3G networks to see who was king. Dongles from AT&T, Verizon and Sprint were used with a Lenovo X300 across 500 data points in eight different locations throughout NY, NJ and CT within 50 miles of midtown Manhattan. AT&T averaged 755kbps download and 484kbps upload speeds with a peak of 1.6Mbps using a Sierra Wireless’ USBConnect…