I am no expert, I just love US armor
but with tracks I'd stay away from Fruils and other metal tracks because of the "sag" they produce. As you are propably aware Sherman tracks were "live" tracks, so in my opinion you'd be much better off with styrene or resin tracks.
Modelkasten tracks are very detailed, but also very tedious to assemple. Panda Plastics make some excellent tracks that I think walk the fine line between level of detail and ease of assembly very well.
Just my two cents worth...
I have no experience with the AFV Club tracks, so maybe others can fill you in there...