Somewhat lost in the news coverage of Clearwire's accelerating launch of Mobile WiMax markets is a simple question: does the service actually work well? As we noted a few weeks ago, there's a significant number of new Clearwire customers in our forums who haven't been exactly thrilled with the new Mobile WiMax service's speed, range or availability. Those complaints continue, with one user e-mailing us to note his experience as a new Clearwire customer has been, for lack of a more scientific term, sucky.

"I signed up for the service on Monday and took it back to my apartment to see how it worked for me," says the Broadband Reports reader, who lives in Dallas. "I noticed immediately that the signal inside my apartment was incredibly low, only 1 bar for service which resulted in sub-dialup speeds." The solution? Opening the window.

With the window open, the user received fully advertised 6mbps/1mbps service. The problem? Closing the window resulted in a complete loss of service. Apparently, the user's apartment windows have an ultra-thin layer of silver molecules to help block UV radiation, something fairly common in new or renovated homes/apartments, but which isn't playing nice with Clear service.

We've fired an inquiry at both Sprint and Clearwire to try and see if they have any additional information. The user, who called in to get a service refund, was visited by a technician that confirmed his window troubles. "The technician also stated that lots of other new customers living in my area were experiencing the exact same problem," and "cancellations in 'newer' parts of Dallas were starting to roll in at a very high rate."

It's certainly not a show stopper, but it could cause a problem for Clearwire deployments in areas with lots of new building developments (until they use femtocells or outdoor-mounted antennas). Some of this stuff is just the kind of early bleeding edge headaches you'll see with any new broadband deployment, but the indoor reception issues join a chorus of complaints about connection quality throughout our forums from users in Chicago, Portland and Atlanta.