Been using the following sites and their tools to find decent films:
These 2 just found so do not have much experience with them:
= more for roku channels
As far as movies offered: my guess is that they are "bundled" and then the rights to show them are sold to the highest bidder. When I signed up for Netflix a year ago or so, I think they had a deal with Encore or some such. Had a bunch of shows and movies in my queue one day and the next day they were all gone.
On Cable you have Fox Movie Channel and Turner Classic Movies for example. Anything to make a buck.