I quite liked it, in particular the first half, thought it was a great performance by Atwell, but when it went from plausible near future to Blade Runner I felt it lost its way somewhat, which is a shame. That said the ending redeemed it somewhat for me, the notion of things being put in the attic nicely foreshadowed it, and I thought it was an interesting allegory for the life of a lot of modern fathers who are no longer with their wives; the kid only getting to see them at weekends and special occasions.
In a way I wish Brooker had cut out some of the sex scenes (not that I'm prudish I just didn't see much point apart from fake Ash being great in the sack when real Ash was a bit rubbish) and spent more time with the family unit. I mean, whilst the mother knows this person isn't Ash, from the daughter's perspective he's her dad, and is a fake representation of him better than just a few old photos? Like I say it would have been interesting to take that a little further.
I'm afraid The Entire history of You was my least favourite of the three, nice idea but done with such a lack of empathetic characters that frankly I didn't give a shit about any of them. The one with the PM and the pig was the worst idea of the three, but it was better, in my eyes, because I could at least feel some connection to the characters. So for me Downey's version sounds like it might be more fun to watch