As above, the 1.4x TC works well in good light with the 70-200mm f4, so effectively giving you a 98-280mm f5.6 so it would still autofocus on a XXXD, XXXD, XXXD, XXD and XD canon bodies but you lose a significant amount of autofocus speed and the lens would hunt (trying to find focus).
The 2x TC loses 2 f-stops, serious hit on autofocus speed and you lose image quality as well and would only autofocus on a 1D series camera body, although you could use manual focus.