sploo wrote in post #17484943
Depends what you're shooting really. The 70-200 range is great for portraiture, and the f/4 is a nice lightweight bit of kit for travel.
I've used the f/2.8 with a 2x TC for "zoo wildlife" and its acceptable, but if I were doing more of that (and almost no portraiture) I'd get the 100-400.
There are also "zoo-like" situations in places like urban parks, where birds shrink their personal safety space to adapt, even unlikely migrants and vagrants who only stop by for a few days. A very close shot (real "reach") with a wider lens makes a completely different feel to an image than a distant "spy" shot. I realized this when I briefly was a member of a photo club (too competition-oriented and judged by people too impressed by cheap Photoshop tricks for me to stay), one of the members showed a photo he called "Mighty, Mighty Sparrow" which was a photo of a House Sparrow nearly filling the frame with something like a 35mm lens, and it was bigger than life, with the background completely dwarfed relative to the sparrow.