For anyone else reading this thread, don't rule out Canon's 70-300 f/4-5.6L IS
All metal, Great IQ, the IS works well w/ 300mm at 5.6
Shorter, wider, lighter that the other big glass, making it a good carry.
Picked mine up 3 years ago from Canon's refurb site - currently on sale for
$1079
Great reach on a crop sensor and doubles as a portrait lens w/ my 6D @ 70mm.
Sample image, interior - 6D shot @ 200mm f/5 1/40 sec, handheld inside a cathedral in France ISO3200, unedited jpeg:
View attachment 326266
Sample shot, blacksnake - 6D @ 300mm f/5.6 1/100 sec handheld, outside shot ISO200, unedited jpeg:
View attachment 326268