I have been with StreamFab since its inception, and purchased a lifetime all in one subscription while it was still in public beata. (Released, but with a great many issues.) It has come a very long way since then. Some streaming platforms allow you to "Download" titles, but still force users through a proprietary interface, require internet, or both. I started with StreamFab, because my internet at the house was very slow, and caused constant and annoying buffering. StreamFab has allowed me to watch movies and TV shows offline with no buffering or commercials without being forced through a data mining interface. It has also allowed me to "snatch" movies or shows before they are taken off a steaming platform forever, and watch them at my leisure. It also allows me to download in up to 4K and keep a small library until my drive starts getting full. (*Resolution is sometimes limited by the streaming platforms themselves.)The war between streaming platforms and downloading software is constant, and there have been periods when DRM changes by streaming platforms have prevented me from downloading content for offline viewing. The FAB team is wonderful though, and these issues are resolved fairly quickly (Usually 1 - 3 weeks (for hard cases)). During these periods, I just use another streaming platform until the issue is resolved. Customer service is very good, and I have had all of my questions answered through the customer service portal, or the online forum. Although it is a constant "work in progress", it is by far the best and easiest software of this type that I have used. Highly recommend.
* Although StreamFab may violate streaming platforms' TOS, this is NOT pirate software. You will need an active subscription to a streaming platform to download content from them for offline viewing.