I've cleared with the boss and I can do either one of these
To use on a 50D for rugby league and general all purpose use

Canon EF70 – 200 f 2.8 L USM with either the

Kenko 1.4X Pro 300 DGX
or the
Canon Extender 1.4 X ii


Sigma 70 – 200 AF f 2.8 EX DG OS HSM with either the

Kenko 1.4X Pro 300 DGX
or the
Canon Extender 1.4 X ii


Which of these two combo's would you recomend and why?
Any pic's would be good as well