I used to try readPST when I had to convert from Outlook to Evolution, but it was quite unstable, especially when faced to nested folders. But I can't remember which version I was using, so perhaps this one is more reliable.
Outport, too, is kind of a mess, in that it doesn't import attachments and loses lots of settings/format; moreover, it comes into trouble when Outlook security issues urge it to close connection as it exceeds some time limits.
Anyway, since I eventually migrated to Mozilla as mail client, using it (Windows sided) to convert from PST and simply copying folders into Linux-sided one is easy; I must admit I'm experiencing some troubles from versions past 1.6 (to import data I often have to make some tries before I get it to work; matter of permissions ), but in the end it sounds like being the best choice.