After numerous misfires, the Sprint Nextel Xohm mobile WiMAX service went live in Baltimore on Monday. While success is still a ways off, with the service now available, many of the long festering questions about the technology and its marketability will finally get a real test. In the meantime, the planned combination of Sprint’s WiMAX unit and Clearwire Communications is on track to close by the end of the year.

I have recounted the travails of WiMAX before, and all of those issues are still key to WiMAX’s survival. At least now we have some price and performance data so we can begin to see where WiMAX fits among the other options for wired and wireless broadband Internet access. Sprint is offering an introductory rate of $30 per month for mobile access and $25 per month for home use. While we still are without Intel’s long promised integrated WiMAX interface, there are USB modems available from ZyXEL and Samsung for $60 and $80.

Sprint is predicting average downstream data rates of 2 M to 4 Mbps and upstream rates about half of that. That $25 per month rate would put them in the same price/performance range as DSL, and well below the generally better performing cable modem services. A 2 M to 4 Mbps mobile service for $30 per month would be far more attractive than the typical $60 per month consumer price for cellular data services which top ends at about 700 Kbps downstream, and downshifts to the earlier technologies and lower data rates when the user moves out of a 3G coverage area.

However, the prices are “introductory” and the data rates are “expected”, so we shouldn’t put too much faith in the press releases. We can be quite sure that we’ll get plenty of real world performance reports in the coming months, which will tell us a lot more about what we can expect from a WiMAX service. If Xohm can consistently deliver those data rates, the biggest response we can expect is pricing adjustments from the cellular carriers. However, the scale of those adjustments will be based on how serious a threat the cellular carriers judge WiMAX to be. It is important to note that WiMAX impacts only a small part of the cellular carriers’ market, mobile laptops. Most cellular data usage (and revenue) is generated by handsets and smartphones like the Blackberry, and those devices lack WiMAX interfaces.

While it is capable of supporting a limited number of devices, in a single market, WiMAX is here. For now it appears that WiMAX will have more appeal to consumers than to enterprises, but however you slice it, competition is a great thing.