I just returned from 15 days in Rwanda, Tanzania, and Kenya. I debated about taking either the Tamron 150-500 z-mount or the new Nikon 180-600 zoom. Due to space and weight, I went with the Tamron, which turned out great. It is much more compact than the Nikon and seemed to performed well. I was happy with the sharpness of the images, although the Nikon 600 reach would have come in handy at times. All in all, I think I made the right decision. Now I need to decide whether I keep them both or not. Seeing and photographing the birds of eastern Africa really inspired me to get more into birding.
I have the 400/4.5 and 800/6.3 and purchased the 150-500 to complement these two. I considered the 180-600 (too big and heavy) and the 100-400 (too expensive and short) and went with the Tamron. I don't use zooms that much. The only thing I really do not like about the Tamron is it's VR. It is clearly inferior to the Nikon lenses in that regard. Other than that, it is quite a good lens.
Since you have both it and the 180-600, I am interested to see what you decide!
I hope you enjoyed your time out here. The birds really are incredible. I have considered the Tamron, 180-600, and 100-400 but haven't made a purchase yet. I'll be moving from Rwanda to India later this year so my needs may change, I'm not sure of the safari environments there. Not a huge birder and the Z7ii doesn't exactly excel here. But for me, as someone who mostly travels, the 180-600 is just too big and heavy. The Tamron then seems logical, but I too am concerned about the VR. I also shoot a lot of landscape and occasional sports, and the 100-400 seems more versatile in this regard. I would most likely purchase the 1.4TC as well and that would get me to 560 if I needed more reach. I like that Nikon is giving us options here though.
