Sorry, but why even bother with people who make such comments?
Even if someone does not know exactly what he is talking about, by implying you are and then making such a cynical comment should be a reason for people not to bite/comment on it.
I think he was just hoping for such a reaction.
OT, I think the 200-400 is a gem, but will probably only be bought by the real pros or people with enough budget to own 2-3 big tele's. Having it as your only big white because your ''budget limited'' would not work for me.
The 400/600 would make more sense from financial perspective.
Also 200-400 is 60-70% more expensive than the 300 2.8, while the latter has better/equal iq at 300-420 and 600 where the 200-400 goes to 560. Putting on converters all the time is not realistic.
With the money and weight you save you could get a 120-300 or 100-400 on a second body if flexibility is really needed.
Flexibility is worth it that you lose 2.8 and little bit of IQ ( however slightly ), but the the increased price over the 300, and price equal to the 400/600 means it is a hard lens to justify(for me). *** Edit the 200-400 is equally priced to the 600 here, and 1100 euros more expensive than the 400 f2.8
The nikon 200-400 makes the choice a bit harder , it is 15-20% more expensive than the 300, yet the 400 2.8 is 40% more expensive than the 200-400. There i did decide to get the 200-400 for it's versatility and price!
If it was as expensive as the 400, I would have chosen the 300 or 400, not the 200-400.
If budget was less or no issue, I am sure the 300 2.8 , 200-400 and 600 would be with me.
Even then I would probably bring the 70-200, 300 2.8 and 600 on safari and leave the 200-400 home.
Switching between bodies is not that time consuming , situations where wildlife runes straight towards you is also rare , and as the cynical poster has suggested , the 200-400 with its bad servo tracking would probably miss such a shot
And a good guide + off roading ability will mean you are not in such a situation, because that is basically driving prey to predator and not very natural hehe
The times we did encounter chases/kills it was parallel to our position , or driving along(i.e) different directions while driving.( It is very hard to keep(or even get) a 400mm 3.6kg lens on target when driving 30-40km/h in the bush , for me it came down to luck to get a few shots in). If there were no seat belts it would have been impossible because if the driver hits an aardvark hole you and equipment will tend to go airborne !