I've tried this several times on a blog that only has 107 posts. The importer finishes sometimes after hitting refresh after a stall and says all done.
I have my posts, users, cats, media BUT the media is not attached to the posts and the links to images inside the posts links back to the old domain.
The import file is only 836k. The size of the images is 307mb. I have split the file but the images are not attached and only some posts have the proper links.
If I import media that corresponds to a post in the same file such as grabbing the first 20 media from the xml and deleting the rest and then cutting out all posts except for those that are parents to the aboe media everything works. This is a painful and laborious process as I will have to do this 15 more times for blogs that I am moving.