I watched the videos. Thanks for sharing the links.
Fantasy Grounds does have Fog of War, but they do not have the line of sight that Roll20 does. It seems FG has been promising line of sight for a few years now, but has not delivered.
Line of sight issue aside, Fantasy Grounds seems like the better deal. According to the first video link, Fantasy Grounds costs less (both initial cost and purchased content). Additionally, User Interface and functionality is better (everything is pre-programmed for you to include 5th Edition rules - no wasting time setting up macros, functions, etc). As a free "Demo" user on Fantasy Grounds, you also get full functionality if your DM has the Ultimate edition. I think it's nice (for DM's) to have the option of "owning" the Fantasy Grounds software and avoiding a recurring monthly subscription.
On the other hand, the user base for Roll20 is much larger than for Fantasy Grounds. For content creation, the Roll20 "free" version is also better than the "Demo" version of Fantasy grounds. With Roll20's free version, if you are willing to put in the time and effort, you can manually input all your D&D books, maps, monster stats, etc. The 2nd video even mentioned you could create any board game (like monopoly), and play it with the free version. The guy in the 2nd video mentioned he spent over 1000 hours programming 5e D&D ruleset, but in the end cancelled his subscription, and bought Fantasy Grounds which he prefers when DM'ing
I have no plans to be a DM, nor do I have any plans to purchase content on either Roll20 or Fantasy Grounds. (I bought the books, and don't want to repurchase them again).
For me, I guess it comes down to whichever platform I can find a good group with. I'm open to either platform. I just need to find a DM willing to have patience with a new player like myself. Roll20 might be a good choice since it has a larger user base. Fantasy Grounds might be a better experience for having a more polished User Interface. I don't think I'll go wrong with either choice. Ultimately it just comes down to finding a good DM.
Another cool takaway from the videos was a highly recommended program called "Maptools". Its free, and you can create decent maps which can be uploaded into either Roll20 or Fantasy Grounds.