Over the last few months, I've inadvertently undertaken a very unscientific study on the networks of three of the major U.S. wireless carriers. I didn't mean to do it -- I just wanted a MiFi that worked when I traveled or was out of my office for a few hours. What I found out was that only two networks are even worth considering, and one is far and away better than the other.

The beginning of the tale  
I started my quest at  Best Buy   NYSE:  BBY ) , because they carry all of the major wireless providers and have a number of WiFi devices. After browsing through some devices I settled on the  Virgin Mobil  3G MiFi, which operates on  Sprint 's ( NYSE: S ) network, because it came without a contract and had relatively inexpensive fees. After a few hours of tinkering to get it up and running, the results were acceptable … until I started to drive. Leave the city and not only does reception become spotty, but the network is also slower than a snail race. When I finally lost this MiFi, I decided it was time to make the jump to 4G.

Next came a short run with  T-Mobile's  4G MiFi, which never seemed to work whether I was standing next to a tower or out in the middle of nowhere. Maybe AT&T was better off without this carrier after all.

At this point, I had learned a hard lesson. If you are in real need of Internet access, don't skimp on the cost. Obviously Sprint and T-Mobile couldn't provide devices that met my needs, and after my experience with  AT&T 's ( NYSE:  T ) decent-but-not-great coverage on the iPhone, I got serious and bought a  Verizon   NYSE:  VZ ) 4G MiFi with 3G capabilities.

I must say, I've been amazed at the results. Not only is Verizon's network faster and more reliable, but my Verizon MiFi device even loads faster than the other two. Sure, the cost is higher, but if you earn a living by having Internet access, it's a small price to pay.

Foolish bottom line  
The power of the network is obviously important to wireless carriers, but I didn't realize the pricing power they have until I did the runaround. When it comes to investing in wireless, there are only two names I would look to: Verizon and  Vodafone ( NASDAQ:  VOD ) , which is Verizon's partner in Verizon Wireless. They pay 5.2% and 3.5% dividends, respectively, and hold an incredible advantage in the U.S. wireless market.