Haven't worked with ASP.net in years, but afaik it's hard to do custom URL routing in it.

(Basically, ASP.net doesn't let you do things you can shoot yourself in the foot with, but that doesn't keep you from shooting yourself in the foot in the language: I remember running into an issue a back-end developer I was working with had with returning JSON from a webservice. We ended up wrapping the JSON in an XML document to make ASP.net happy)