I first read this title as Catastrophic Design Differences, which isn't far off. The author is biased in favor of Google Maps (it's a bit hard to differentiate between Google's 1st and 2nd level city markers), but I like the comparison.
I don't think its biased. Google is clearly more legible and useful. Bing is so so but way too many quirks and unuseful stuff, less legible, Yahoo is just insane. I don't think I've ever used Yahoo so I didn't realize just how bad it was.
Very interesting reasons and analysis of the small differences that all add up to Google maps market dominance.
