My understanding is that there are saved stories and meta data that you can't export from google reader (mostly based on comments on this thread https://news.ycombinator.com/item?id=5371725 because I don't use Google Reader and never have). Is my supposition incorrect?
The way they export your favorites / shares is just a json API that isn't standard. Services will rapidly pick up importing from that format, but besides the feed xml file none of what they give you is that portable.
