Ken Rockwell says:
This is a great lens. It is super-sharp at every setting and covers such a huge range and focuses so fast and so close that it can replace several lenses — if you don't mind the huge size, weight and price.
You don't need a tripod unless you're using teleconverters. I easily hand-hold this beast with its excellent stabilizer at 600mm.
Jared Polin says:
At 60mm, not super sharp, gets purple fringing. At 600mm,it is super sharp, no edge fringing. Beginning around 100mm, it's good. Overall very good lens and happy with it. But it's $2000 at 6 pounds and not so easy to use due to weight. If you think of it like a 100-600 vs a 150-600, he like's having that extra 50mm range.
Personally, I don't see why I'd lug 6lb around vs 4lb on the 150-600. At 6lb, I'd frankly step up to a 500mm f/4 (like the Sigma at 7.6 lb or a used nikon G at 8.6 lb). I don't think I'd like carrying 6lb plus camera and gear for a long time.
I'd rather carry a separate RX100 (under 1lb with lens and battery!) or similar for the 24-200 range and keep a 500mm f/5.6 or 150-600 on the DSLR. Usually, for me, the shorter focal lengths are for people I'm with and the longer are for wildlife, and I can keep the camera's setup for those different purposes.
Marc