[Neoprene] I got this lens as a gift from my mother. It is the best gift ever. It is very heavy and you need a tripod to use with it. I tried using a mono-pod, but had better results/luck on a tripod. I am not sure Arnold Schwarzenegger could hand-hold this one for long, even in his youth!
There is a learning curve and some adjusting to get used to it, but it is a great lens for wildlife. I was lucky and got this as a gift, but if you have the $$$, it is a great lens.

[Neoprene] I am a very armature photographer and the shot's I got with this lens makes me look like a pro.

[Black] This lens is heavy, large and well, repeat WELL, worth carrying around. Autofocus is quick. Quality is excellent. Some have commented that long lenses are like looking through a drinking straw. I don't find the narrow field of view that extreme but still need practice in quick and accurate aim. I do wish the 800 would autofocus with a 1.4 extender but that does offer some practice in long-neglected manual focus skills. The Kata TLB-800 PL Lens Backpack has already proven itself excellent in getting the lens and camera to the scene of the action.

[Neoprene] I finally managed to purchase this lens after 28 years of wanting a big glass. I looked at many different lens's some much less expensive and decided to go for this big gun.
So far i found that the clarity and use is top notch. My photos have gone from OK to WOW! I mainly shoot wildlife and this lens lets me get those close shots that are National Geo quality without harassing the animal! I really love that as I can shoot them in more natural positions and they stay put for more opportunities for that just right position.
Heavy? 9.9lbs,plus the tripod and lens mount does push down on my shoulder, but it's relevant. I can carry it for miles and only complain a little about a sore shoulder the next day. I'll get some more padding to relieve that situation.
Over all I have finally got my hands on the best lens out there! Love it!

[Neoprene] Having had this lens for a few months I would say that this is the Bees Knee's when it comes to long range photography.

[Neoprene] I have only had this lens for 10 days and I am amazed at how this lens tracks birds so well. It was not hard to find the birds through the lens and then keep them in view, shots were very sharp. I also took pictures of whales from quite a ways away and the pictures were so good I didn't even have to fix them in Lightroom. Even with the wind blowing about 25 MPH this lens was still tack sharp while on my tripod. I really can't name anything about this lens that is not great. It is just a little bit heavier than my 400 f/2.8 so you can take some shots while just holding it. Where the 400 f/2.8 did not reach far enough for me, the 800 f/5.6 takes care of those long shots. I didn't have any problems with it being a f/5.6 instead of f/2.8. I would highly recommend this lens!

[Neoprene] It is excellent. Exactly what I needed. There is nothing not great about it, everything works fine.