Pull DP's are a great idea, however they are quite error prone and often just stop working. Search in any Configuration Manager forum for Pull DP's and you will see the same thing over and over, which is they often get stuck at "downloading content" and the only way to rectify it is to uninstall/reinstall the pull DP.

As I said, I really like the idea of Pull DP's. But I would like to see the product team spend some more time on them to really get them working as efficiently and effectively as possible.