I like the fact that I'm running un-altered source as much as possible, that I can report real problems upstream and help contribute to Hackage in general, and also there may be subtle bugs with jailbreaking, when type classes change their meaning (though we haven't really observed that problem yet).

You replied by saying "if it broke once it might break again", which is of course true. On the other hand, we seem to break Haskell packaging on `master` fairly frequently anyway (for example, we updated `authenticate-oauth`, which still doesn't build until upstream resolve some issues).