Would be a shame to see Blinkbox go. I only watch films infrequently, but it is nice to have the option to watch one without taking out a monthly subscription to channels filled with loads of American TV carp.
Because it isn't an all you can eat service, it tends to have a better choice, whereas the sub channels only have some stuff for a limited time. I assume because the royalties are on pay per watch.
Sky store is apparently similar, but I haven't tried that.