This is the first "theatrical" (i.e. live actors, not cartoons) realisation of a Terry Pratchett novel, and like, I'm sure, all Pratchett fans I approached it with some trepidation. Would it work? Would the intricacies and atmosphere of the Discworld be adequately represented for us here on Roundworld? Could they be? It was a bit like going to see the first of the "Lord of the Rings" trilogy at the cinema - could such a different place, which each of us believed in in our own way, actually be filmed successfully? The answer with the Peter Jackson film(s) was, of course, a resounding "yes" and the same goes for this less ambitious venture.
There have been cartoon versions of two Terry Pratchett novels, "Wyrd Sisters" and "Soul Music" and these worked reasonably well, but the limitations of the media (and some rather quirky editing) mean that we had to wait for the live action "Hogfather", with excellent casting and production, CGI, and animatronics to start to do justice to Pratchett's vision.
It is difficult to fault it. The only thing the viewer has to take care about is that as well as enjoying it you have to pay attention because otherwise you will miss some typically Pratchett little gems, and possibly something relevant to the plot. Discworld devotees will appreciate it most, I think, but others should too, judging from the positive reaction from my family members who have hitherto resisted the novels. And yes, it is worth buying the two-disc version.