Upload & Sell: On
When shooting with a manual focus 400, 500, or 600 you tend to predict where the subject moves, prefocus at that distance, then as the subject moves through the plane you shoot. Then refocus and repeat. If you use a cable release you can let go of camera and lens while shooting, and possibly even use MLU sometimes, and not even look through the viewfinder as you shoot. This eliminates a ton of camera shake and your speeds become limited by the need to capture subject movement.
It works, and will give you tons of technically excellent shots. But the drawback is that with a long lens DoF is so shallow the subject spends almost all of its time OOF to some miserable degree, then only briefly passes through focus. So anything interesting is bound to happen while it's OOF. The gesture, the accident, the cyclist breaking away throwing a glance over his shoulder to see how far back the peloton or the rest of the breakaway is. So you shoot anyway and hope the results are salvageable. Because interesting trumps technically good every time. As you grab the camera and jam your eye in the viewfinder to shoot there is shake to boot.
AF has completely changed this. Now you track the subject, holding the camera and lens, continuously eyeing the scene through the viewfinder. The big win is the subject is continuously in focus (or some very close approximation thereof) - a vast improvement, because now when you see an image you simply tweak the framing and shoot. But the side effect of this hands-on approach is that there a lot more shake going on. If you haven't used a 500 or 600 it might be hard to imagine, but you can see even the flex in the tripod foot as jitter in the viewfinder. Even a Wimberley gimbal head has visible amount of flex. No matter what the setup, some gentleness in handling is required.
This is why I would NEVER buy a lens in the 500 range without AF (because it's not worth my time shooting without it - I want interesting images, not just crappy page fodder), and because I'd only buy an AF lens I'd never buy one without stabilization. (Or at least a body with stabilization.)
(Actually, the last sentence is a bit of an exaggeration. I have a 500/5.6 for my Mamiya 645 that I use on my Sony A850 with an adapter, but it has all the limitations mentioned above.)