Compared with Google's ditu.google.cn and Sogou's (搜狗) map.sogou.com, the site seems about the same, if a little faster--though traffic may still be low. What Google and Microsoft have in common is that the maps contain listings for restaurants, banks, and other locations rendered as icons on the map. Sogou has no such advantage, but sometimes it resolves addresses better than Google.
But here's the interesting part: Microsoft's new service includes major highways and the locations of main cities on Taiwan. It never occurred to me before, but so does Google's. Sogou, on the other hand, has a full detail map of Taibei (Taipei).
Is it just me, or does this suggest that Google and Microsoft may have struck a compromise between people who would want Taiwan included and people who would rather see it separate? Google has a much better map of Taiwan on Google.tw.
I don't want to suggest there isn't a good reason to have different map sites serving mainland China and Taiwan audiences. Here in Beijing and throughout the mainland, we use Simplified Chinese characters; in Taiwan, they still use Traditional characters. This is important because place names look different in the two systems. Even the word China is different: 中国 (Simplified) and 中國 (Traditional).
It's perhaps unsurprising that Sogou's Taiwan map uses Simplified. But it is interesting that both Microsoft and Google have included partial map information for Taiwan on their mainland-focused sites. For another day, perhaps I'll look at where they drew the international barriers at sea, but we already know making maps can be a source of controversy. Just look what happened when a Chinese-made map for sale in Japan was recalled over labeling Taiwan.
UPDATE: Just as I finished writing, I noticed a headline from Marbridge Consulting's Web site noting that China's State Bureau of Surveying and Mapping recently published a to do list for 2008, including the drafting of a document all three sites would be wise to watch: "Suggestions on Increasing the Supervision and Management of Mapping and Geographical Information Websites."