I streamed the main Crown of the Magister campaign and played through the Lost Valley twice. It's my opinion that LV is better, although in its initial release it had a lot of errors and glitches. The current release is a lot better, but certain endings are still locked out due to glitches so save often and in multiple slots.
The main campaign is pretty straightforward and simple, and it's major emphasis is being able to play what is basically the most authentic "5th Edition experience" as a video game. But the main campaign is also the weakest of them IMO, although you should still play it as it introduces some concepts and tutorials that aren't in the other campaigns. For instance, it adds a crafting system that isn't available in the tabletop rules.
Much like actual tabletop 5th Edition, I highly recommend checking out the modded campaigns. Some highly regarded ones are the Temple of Elemental Evil which is a pretty faithful conversion of the original module, and Through the Realm of Mysts is pretty much copyright-friendly Ravenloft. These are both ones I played, and thus can recommend.
Finally, I highly recommend Unfinished Business. It's a mod that more or less converts all of the non-OGL core WotC material into the system, and it's still getting updates to this day.