I purchased one of these early in the year and I can confirm that it definitely is a viable option, particularly for those on a budget. Having just purchased my VP2, I couldn't afford the Davis options. I used this to connect via a Keyspan serial to USB adapter with my Mac Mini running 10.6 Snow Leopard (the Mac operating system) with the latest Apple OS patches and Keyspan drivers. The Keyspan adapter was brand new as well. (I'm running Weathercat Mac software on the Mini to handle my data logging, graphing and uploading to WeatherUnderground.)
The only issue I had, which I'll post here for the benefit of others who might try this, was an occasional loss of the data feed by my Weathercat software. All the software was up to date, so I added ferrite cores EVERYWHERE to try to eliminate any interference. This did not resolve the problem. I also noted that when the Mac lost the data feed the VP2 console also locked up. It wouldn't respond to key presses for around a minute or so. Then everything went back to normal - although the Mac still had lost the data feed. I used a watchdog feature of the Weathercat software to force a recycling of the Weathercat software. This would reestablish the communication and all was well again. This resulted in a few minutes of dropped data 2 or 3 times a day on average. But everything was fully automated, so for the cost I found it a very acceptable solution.
Since then, I've "recovered" from the cost of VP2 and just purchased the Davis WeatherLink IP logger. My WeatherCat software is able to poll from this logger without problem even with the logger firmware also uploading to the Davis WeatherLink site as well. (I know I could move the uploading to WeatherUnderground from my Weathercat software to the Weatherlink site, but Weathercat is working just fine.)
Even though I'm not presently using my DSO-01, I applaud the effort at creating it. I have no problems recommending it for those looking for a much less expensive solution for capturing their data than what Davis offers.
I would also add that having moved to the IP solution, I can't imagine going back to USB or serial. The IP seems rock solid, plus my console doesn't need to be next to my computer any longer. If Davis could just imbed a wi-fi chip in their IP logger then it would be an even slicker solution. However, it wouldn't completely free the console from cords as the IP logger MUST have the wall wart attached. The batteries will only power a console with the IP logger for a very short time - I think measured in hours, if not minutes.