Don't do it!
I can shorten this review significantly - don't buy any of it! These are still at early adopter prices, the sort of money you'd once have paid for a standard Freeview box when they were new - you know, those boxes that you can now pick up for £20. The HD service itself is very limited at the moment and won't roll out to many areas for another couple of years, by which time these boxes will be substantially cheaper and £170 will by you an HD personal video recorder, not just a dumb set top box.
Don't be a mug, save your money and stick with SD Freeview for now.