30 days to watch a movie is a long time. I think it would be 30 days to start watching it and then either 24 or 48 hrs to watch it once you start.
If it goes that way, why even set a time limit to start?

If once I start it I only have 24 or 48 hours to run it, what difference does it make when I start? If I'm willing to use up the storage, lemme just tuck it away for good until I'm damn good and ready to watch it.
OTOH, I do like the idea of being able to watch it over and over for the whole 30 days. Not that I myself would, but maybe I'll watch it one day, then other members of the household could watch the same thing at their convenience during the 30 days. That sure beats the hell out of a 3-5 day rental from BlockBuster (brick and mortar, that is).
I do understand a lot of people's preference for a real DVD for quality and extras, and the strong desire for HD versions, but
not everybody has an HDTV with a massive surround sound system. Some of us poor folks still have 480p only. Lots of us, in fact.
I think the 3/4/5 dollar options for various resolutions is a sound solution, however. Not only are there more costs involved in prepping 720 and 1080 versions, but the bandwidth to deliver needs to be factored in, too.
I'd like to see an "apply rental to purchase" option as well... Similar to "complete my album" for music. I think they would succeed in selling more full purchases that way... Sort of a "try before you buy" option. Again better than renting a DVD from BlockBuster, finding that you really like a particular one, then still having to pay full price for a keeper.