I'm considering dropping Netflix to save some money, and going solely with Amazon Prime. For one thing they still have spongebob, which my kids watch and is as a result probably 90% of our (former) Netflix watching. So now we are using Amazon way more than netflix. I will miss out on the Netflix originals and some other stuff, but we are a bit tight on money since having to buy a new car. But I'm not sure. Netflix has a lot of movies I'm interested in. I need to check and see if they are on AP as well.
AP's selection definitely isn't as good as Netflix's, but still pretty decent.
Personally I have Netflix disc service for Blurays, and just use Amazon Prime for streaming since I already have that service for the shipping.
I don't watch enough streaming to pay for it as I mainly watch newer release movies these days--and thus need the disc service. And AP is a nice fill in when I'm between rentals, don't feel like watching something I own (or I'm at my girlfriend's place) etc. If I was watching more streaming I'd probably splurge on Netflix for the better movie selection though.