Watch Cordkillers 292 - Don't Be Ridisculous (w/ Fraser Cain) where Fraser Cain details how he used his watchlist on Just Watch to create a spreadsheet of how many movies and TV shows he wants to see are on each service. He then further took the monthly cost of each service divided by the things he wants to watch to figure out the ones with best ROI. If you are looking to budget ths is a pretty quick and easy way to do it. Though I might suggest of there are any deal breakers (stuff you do not want to lose access to) you may want want to add some columns for those as well to mark what service(s) they are on so you do not drop the wrong one.
Just Watch is an awesome free service by itself. It is similar to Roku's watchlist feature where you can just plug in the stuff you want to see and the watchlist shows what is available on what services you subscribe to. With the added plus it is a well formatted list instead of Roku's notifications format. It also makes it easy to see if something is available on a service you do not have.