WAY too rich for my blood

...especially when the difference between the $1200 f/4.0 and the
$3000 f/2.8 is overcome by just switching from ISO 100 to ISO 200.
The difference in depth-of-field between f/2.8 and f/4.0 isn't much on
a 300mm lens.

Sure, in very low-light situations it's not all that simple, but
*myself*, I do very little telephoto work in that low of light.

I think that a lot of people do get caught up in "lens envy". For
every person who regularly shoots moving birds with a 300mm lens and
1.6x teleconverter at dusk, there are an awful lot of people for whom
even a "lowly" 300 f/4.0L would be much more than sufficient well over
99% of the time.

steve