canon 70-200mm with 1.4x tc or sigma 120-400mm

[Morph]

Hi all, just wondered if anyone had any advice on what to choose. Do I stick with my Canon 70-200mm F4.0L and get a 1.4x tc or do I sell the 70-200mm and buy sigmas 120-400mm. Im on a budget so im a bit stuck (unless someone wants to sell me a sigma 80-400 ex cheap!!)
Neil

 

[rileydoggy]

personally, i'd stick with the 70-200. It is one of the sharpest lenses you'll find.
I think either way, with the sigma or the 1.4x you'll find that you'll lose IQ

 

[MJ Stebbings]

Sell me the 70-200 F4L, or trade me for my Tamron Thats what you should do!