Is the Sony FE 600mm f/4 GM OSS good for wildlife?

Yes. The 600mm reach and f/4 aperture suit wildlife, especially in low light, and the light weight and rear-biased balance make handheld tracking more practical than most 600mm f/4 lenses.

How does it compare with the Sony 400mm f/2.8 GM?

The 600mm gives more reach for distant subjects, while the 400mm f/2.8 is faster and shorter. Sports and wildlife shooters who need reach usually pick the 600mm; those who want a brighter aperture and closer framing pick the 400mm.

Does it work with Sony teleconverters?

Yes, it is compatible with Sony's E-mount teleconverters, which extend reach at the cost of a narrower aperture. Check the specific converter for the aperture and autofocus behavior you get.

At 6.71 lb it is light for a 600mm f/4, and the rear-biased weight helps. Most shooters still use a monopod for long sessions, but handheld panning is realistic for short bursts.

The lens ships with its front and rear caps, a lens hood and a tripod collar. A soft case is typically included; confirm the exact bundle with the seller.

Does the fluorine coating matter?

Yes. It helps keep dirt and fingerprints off the front element and makes it easier to wipe clean in the field, which matters when shooting in harsh conditions.