Yeah, that's normal resolution. For my purposes (VFR only), the resolution is sufficient as I need to be well clear of the purple, red and yellow pixels. Given the potential time lag of an doppler radar image, the pixels provide what I consider reasonable temporal resolution as well as spatial resolution as the storm can move quite a bit between the time of the first and last bit of data collection and analysis within a particular volume of space (4-8 minutes between updates). I feel the pixel size is a good representation of the "smear" due to the data collection, analysis, and presentation time while a storm is moving. The XM (and ground-based) images I see do look a lot nicer but I'm not convinced they have more accurate, useful, data, especially when imaging a fast-moving storm system. Each of those pixels look to be about a square nautical mile in area and I'd probably would want to be at least 20 pixels away from any thunderstorm for my type of flying.