I'm this lens on every shoot, esp events. LOVE it!
- My main worry was low light performance as compared to Nikon as I often shoot in hotels room during conferences.etc
However this proved to be unfounded. It never has any problems locking focus and focuses fast. The OS works very well, and I most often has it set to setting1 as it allows me to shoot at lower ISO.
- No front/back focus issue on my D700. Sharp even at long end which I v often use.
- With regards to the reversing of focusing ring. Firstly, not many is gonna use it with it huge lens hood reversed. Google online for its pics..its a monster and almost looks like you can stab someone..lol I do not use it on my shoots. Also I remove tripod collar.
- Secondly I've found that it works great with the zoom closer to the hood as I'm able to adjust zoom using my index finger tips, pointing frontwards.
Other fingers still firmly on lens, minimal movement.
Hope it helps. Glad I did not purchase the Nikon as I can cannot fault this lens. I believe its also lighter than Nikon, which of course is v helpful.
Cons: Of course, I do agree it'll have lower resale value, not sure abt servicing, etc.
*Has not posted any photos online using this lens yet. Well Nikon mount here too.

With tripod collar easily removed, I slide into the thinktank pouch when not in use.