@Mark k. - The blogger importer is a shambles too. It routinely brings in just titles with no post bodies, for example, and because you're working with an external API, it can be pretty much impossible to debug issues like that, especially when it reproduces only intermittently with other users' accounts.

Another big hurdle for importers -- and especially ones that poll APIs over and over to fetch data -- is that they can be long-running processes, and the WP cron system isn't ideal. If nobody's visiting your site, your job won't run and your import won't finish reliably or quickly. Even if you use an ajax request to keep the import job alive from the import page, what if the browser crashes or the tab gets closed and you lose state?

I don't mean to throw up my hands helplessly or anything. I mean only to say that the problems around importing are complex; there's a reason these things don't work optimally, and there's unfortunately not currently a real silver bullet. I'm definitely glad to see that there's a GSOC project to try to make things better, though. :)