I bought myself a Playbook last week for $85 used via online classifieds, with the official leather convertable case, and I am elated. To compare it's performance to the Vox is a joke. The Playbook is a fire breathing monster...with nothing to do.
I have come to grips with the lack of netflix, which is the main app missing. Most other functions work fine. Some dislike it, but the Kobo app on it is fine unless you want to add books from non-Kobo sources, and I believe you can load the Android Kobo reader on it if you have the older firmware.
As a tablet, the Playbook destroys the Vox, and spits out it's obsolete-on-launch wussiness. As a reader, I think the Playbook wins as well, though the Vox takes a greater variety of books with the default apps, and the Reading Life gimmick was fun.
In short, at a clearance price, the Playbook is DEFINITLEY worth it to someone who wants a tablet that can read books as well. It's multitasking, video playing, and web browsing capabilities are absolutely stunning.