There is a comprehensive description of the service over on informitv, having signed up yesterday I agree with most of the description. It is certainly nice to see someone get away from "lets do a drawing of a physical device and then try and put UI on it" and develop an interface for working with on a computer.
Even so the interface has some 'quirks' I don't like; it can't be maximised to full desktop size, the scroll bars don't work that well, finding a movie can be a bit cumbersome - it didn't seem that the genre lists included all the films on the A-Z list (but I may be wrong) and the whole thing was a bit cramped on a 1400x1050 screen.
The first decision to make is "which PC does it go on" - it really will only work on a single PC so I decided on the Tablet PC on the grounds that putting it on my work desktop would mean I would spend my life watching films rather than working and since peer-peer is involved here I didn't feel comfortable having stuff upload from my disk without my explicit control. Do I trust Sky to write software that doesn't accidentally upload stuff it shouldn't? For that matter, do I trust the BBC who are using exactly the same technology but with a UI developed by a different company (or in house, dunno)? and the answer is no in both cases. At least I can have the Tablet switched off most of the time and it isn't chock full of confidential data. The other advantage of using the Tablet is its portability around the house and to the car; the kids can download movies before we go on a long trip and have something to do to pass the time (when the PSP, MP3 players etc have become dull!).
Downloading films is slooooooooow - the Sky PR and the above mentioned review state that on a 1MB link it should take about the same time as the length of the movie. For the first movie this was about right, but I have a 2MB link so it took twice as long as 'advertised' - the second movie was 77mins and took over four hours, a 100 minute movie took about two hours this morning. The Tablet is running on a 11Mb wireless but it is clear that download times are going to vary and one needs to leave more than enough time and the Tablet on full power, don't standby/hibernate etc.
Movie quality is variable and not adequately described on the otherwise excellent 'details' screen. Alien Directors Cut is delivered at 500K vbr and not widescreen - its certainly watchable but high definition it isn't. Garfield is delivered in widescreen format at 800K vbr and the quality is obviously a lot better and very watchable. Part of the problem on quality is taking stuff encoded at something like 540x432 and then scaling it up to the 1400x1050 that the Tablet works at. Overall it would seem: expect less than DVD quality.
There's 200 movies available at the moment, and for this number of movies a good mix. Out of 200, probably not that many that I or the kids are particularly interesteed in but enough and as the collection grows to the alleged churning 1000 there will probably always be half a dozen movies one could take on holiday.
Overall its good, movies is much more interesting to me than old/new episodes of Little Britain so, even though I've only seen screen shots of BBC iMP, it looks like Sky 1 : BBC 0.
The final parting shot is that the industry is in one of its "this is the future" (i.e. Internet delivery) modes at the moment - not until they get the quality sorted out it isn't and quite clearly the Internet is going to be a download pipe, not a broadcast carrier. That both Sky and the BBC are going for peer-peer solutions would seem to indicate that they are both terrified of the bandwidth and infrastructure costs that IP broadcast might imply, even if all the households had enough incoming bandwidth. Perhaps they are both being chicken; peer-peer is a cheaper way of dipping toes in water. Of course, what is really weird is I have a very high bandwidth pipe into the house in the form of a satellite dish already (over 12Mb?), and that pipe fills a box with movies etc. Wouldn't it be a better solution to just let me connect the Tablet to the Sky+ box and copy stuff off? Obviously some DRM would be needed but using copper for delivering very high bandwidth content doesn't look like a great runner to me. To use Sky's broadband service, you have to be a Sky subscriber, I think they would be better off looking into how they can develop the Sky+ box into a more interesting device.