Just as an experiment I tried to import a recent story from my Tumblr blog at stoweboyd.com here. That post includes an embed of a Soundcloud song, and when I imported it, the embed disappeared.
However, when I paste the link here manually, it works:
So, in one sense a small glitch. But consider the headaches involved if you were to contemplate porting a blog of hundreds or thousands of posts. I have 9,658 at stoweboyd.com.
Yes, the rest of the post came along ok, but any non-standard styling is lost, of course, because the design aesthetic of Medium is to not put those tools in our hands, at all.
Oh, and there is no way to directly import in bulk — more that a single post — from Tumblr, either. Anyone wanting to do that has to go through one or more ricochets — like importing to and exporting in bulk from Wordpress along the way.
It’s ridiculous that Medium can’t import from all the major platforms. Although, to make things fair all around, it’s ridiculous that Tumblr doesn’t support exporting, either.