Assume that you have good light, proper shutter speed, and aperture for a hand held static shot. Was the auto focus consistently accurate? Or would you resort to a burst of shots to ensure you got one good focused shot?
For myself, so far, I'm finding the burst to hope for (not ensure) a good focused shot is the best strategy. Note - it was much less so using my Sigma 150-500. With it, I pretty much knew on a single shutter click whether I had likely "nailed it" or not. It might simply be a matter of familiarization, but so far, for me, with the Tamron, most the time I think I have nailed it, I actually have not. Thus, spray and pray...
From reading this thread (at least most of it), it sounds like there is a real learning curve in using this lens even for those that have a 100-400 or 150-500. I would then assume that your keeper rate is much reduced in using this lens say versus your other zoom that you have (at least to this point in time). Would that be a fair statement?
Again, speaking only for myself, that isn't just a fair statement, be a dead on accurate one. My hit rate is definitely a good bit lower with the Tamron that it is with my Sigma 150-500. But, like I keep saying, I really don't have the experience, can't say, whether that is simply me and how much more difficult shooting 600 is than 500, or it's just that the lens is a finicky SOB. Whatever - for me, yeah, keeper rate is much reduced.