Extender for 200 f/2.8

I am interested in a 1.4x for my 200 f/2.8. How does this lens work with extenders and which one would be better, the Canon or Sigma?

I would either get the Canon TC or a Kenko TC. Me personally for what its worht I would get a Kenko TC simply because it works on all lens brands and more lenses in general.

The lens works great with extenders - even with the 2x. I use a Sigma, but doubt there's much difference between Sigma's and Canon's.

I have the same lens and use a Kenko Pro 1.4x which works great. Autofocus is fast and great IQ.

No hesitation to use my Sigma 1.4x and even the Sigma 2x is pretty good.

The Canon 1.4 works very well with the 200mm 2.8.

Thanks for the feedback! I like the Canon just because I like to keep all equipment possible with Canon. I like the Sigma beause it matches the black color and I no longer have any white lenses. Can you all post some pictures taken with the 200 and a 1.4? Also, please let me know what cameras they were taken with?

Shot with a 30D and Sigma extenders.

1.4x - 1/400s f/4.0 at 280.0mm iso250