Our X3 (delivered early March of 2011) with nav system, while not always up-to-date (we still have the original map data), has never been as bad as you describe. I wonder if you're having antenna problems or some other issue affecting the data feed or power to the receiver? It's unlikely to be the receiver itself which is mostly contained in a single chip. It'd be interesting to compare your system with another at the same time and location. Perhaps your dealer could help with this? I find the system, as is, very usable and useful, at least as good as my Garmin which has the "latest" maps.
An aside: I find it amusing to read complaints about the cost of map updates. Yes, once created, it costs almost nothing to distribute but it must cost a fair amount to collect and process the data. Are the companies doing this making obscene profits? I don't think so, their stock prices would be a lot higher.
Dave @7500 feet on the plains in Colorado
2011 X3 35i - Blue Water Metallic