I have had Prime since it started pretty much and find the rate that they put out new things pretty poor. I regularly check amzprime.maft.uk as they seem to keep up to date with what's on there. I noticed that last week in one day they added 228 films and TV, having read through the list I think that there was one, maybe two that I was interested in. I have now seen everything that I want to and only check on new additions. They also did a cull this week with 333 removals yesterday and another 48 today, may be they are getting ready for something...
Anyway I started a trail of NowTV at the weekend and am enjoying a lot of the films on there.
I suppose that NowTV seems better as it is a new mix of films but it depends on the refresh rate as to whether it is any good long term.