For a choice of a medium to long Supertelephoto lenses which of the two options do you thing makes more sense ?
The upcoming 200-400mm f4.0-5.6 TC1.4x Lens
or the
Combination of 300mm f2.8 L II and TC 1.4 III + TC 2.0 III which gives the three distinctive focal length of 300mm f2.8 : 420mm f4.0 and 600mm f5.6
Also think about issues like weight, transportability, handling etc ...
The upcoming 200-400mm f4.0-5.6 TC1.4x Lens
or the
Combination of 300mm f2.8 L II and TC 1.4 III + TC 2.0 III which gives the three distinctive focal length of 300mm f2.8 : 420mm f4.0 and 600mm f5.6
Also think about issues like weight, transportability, handling etc ...