You can use these websites to check if a film/series is unavailable to download. Most of the time they share the same torrent trackers so you can have a hit or miss. Nobody actually store any of those on particular servers just waiting to be radio'd by the users. Unless we're talking Amazon Prime! Yes, it is worth every penny, at least so far, for me it did, it's why I've payed in the first place. It has a universal library consisting of both films/series and docs. I actually let the idea of torrenting down lately — mainly because I am fuckin happy to stream at the ethernet speed of mine, in either 1440p or 4K.
Some old films lack 4K but their 1080p can upscale to a decent 1440p resolution.