Re: Sky and UHD
I used to think the same as you with Blu Ray and DVD, and even when I eventually did buy a BR player I was a little disappointed that the movies didn't look too different - I certainly didn't see any great picture quality revolution like you see on the demos in-store.
That was, until I watched a DVD after exclusively watching movies on BR for a couple of weeks. Back-to-back the difference is easily visible to me, and on the whole BR discs aren't much more expensive now than DVD was 5 years ago. DVD is cheaper still now, of course.
I have to say though, I do enjoy a well-encoded 3D movie very much on my passive 3D screen (I'm very sensitive to flicker). I realise I'm in a minority here, but I've always had a penchant for stereoscopic 3D tricks. Jurassic Park 3D is surprisingly good, you could almost imagine it was shot for a 3D presentation. I was hoping that the new LG 4K screens (with passive 3D again) with their double resolution would be able to play 3D 1080p at full 1080p per eye instead of the half-vertical res I get right now, but apparently they don't work like that. Shame. Still, resolution is slightly less important (since your brain merges the two images) in 3D presentation than flicker or crosstalk, both of which are great on the passive system.
Personally, I'm looking forward to a 4K screen with passive 3d that works well and allows 3D 1080p content to be displayed perfectly. In order to replace my not-very-old 1080p set, it will need to also have HDR and an upscaling option which will turn each 1080p pixel into 4 4k pixels would be nice for gaming. Fingers crossed something will appear in a year or two when the HDR specs are final.