While getting frustrated waiting for the Vu+ I am looking around at other boxes..

Two have caught my eye:

The AZBox - native 1080p - able to read 4:2:2 feeds with a sensitive tuner, runs Linux.....

The S4000 2 tuners in a Linux box ?100 cheaper than the Vu+

So why haven't these tuners captured the imagination of the punters like the Vu+?
What are they better at?
What are they worse at?
Why should I not buy one of them instead?