Per a lot of mixed reviews, we decided to take a day trip to Kutná Hora to see it for ourselves. The city itself was once a major financial capital and booming city because of the silver mines and minting business. Because of this, there were a lot of churches built in the area for the miners and their families. We were able to visit St. Barbara's Cathedral - you can see the family crests of those who donated to its building on the ceiling.
The major "attraction" in Kutná Hora, however, is the Bone Chapel. While it was quite odd to see over 40,000 skeletal remains in pyramids and hung as chandeliers, I felt it was very poorly maintained and didn't quite get the feel for why it was such a big deal. I probably wouldn't do the tour again, but if you've got time in Prague it might be worth a visit.