Quote Originally Posted by HDNitehawk View Post
I don't use the 16-35mm at all.
If I don't use a lens much at all in a 12 month cycle, I sell it. Now I have just four (although my wife seems to think I have 10). Makes it easier (both cash-flow and mentally) to fund that next big lens purchase? So what's mine going to be....I drool over the 500 II, but it's not gonna happen any time soon.

But to your earlier question, I'd get whichever lens you will use most often in the greatest number of shooting scenarios. I know that for me, between the two, I would likely use the 500 more; the 600 is pretty darn big.

BTW, I'm not fully following your conclusion that the 600II with a 2x has worse IQ than the 500II with a 2x. To my eyes the center actually looks better on the 600II with 2x; but the corners are much better on the 500II with a 2x.