A good review of most of the systems available for play. My only addendum is that the burden of knowing of and choosing the system is usually added to the GM's job. GMing is hard work and if the group expects their GM to know multiple systems it might intimidate would be game runners. I would add that if you only know of one system or you know you want to run a game in a particular system you can always look for a group that is looking for the same thing. A good group would cater to the largest denominator so if the group wants 5e and the GM has his mind set on SR they could either agree or look for other players/GM.