Alex, thanks for clearing that up. I rate "best" based on several categories:
fit/engineering, accuracy, detail, and "OOBness" or the ability to build an accurate model out of box without the need to add expensive aftermarket resin,aluminum barrel, photoetch, tracks or anything else to have a great kit.
A couple of the best modern tank models made in injection plastic that do not require any aftermarket accessories are the Tamiya Leopard 2A5 and the Tamiya JGSDF Type 90 Main Battle Tank. These are two highly accurate kits that kits are a dream to build.
I hear good things about their new T-55A kit, but have not built it. I also have their JS-3 Stalin tank. It is a superb kit as well, but experts say it has accuracy issues (apparently they used a pieced together museum display tank as their prototype).
BTW, Tamiya's M1A1 has plenty of accuracy issues, but has superb fit and builds great. Too bad it hasn't been redone to the Leo and Type 90 standards.