Over a year later, how do I feel about this lens?
In short, I don't think anything has really changed much.
The zoom action may have got a little looser. Used horizontally it feels like you'd expect a zoom lens to. Pointed steeply in either direction it takes a bit of effort to overcome gravity, and left alone in the mid range it will creep.
The AF I've tried to use more in servo (continuous) mode, where it is mediocre at best. Slow moving targets are fine, but for fast moving subjects it struggles to keep up.
Optically, again that hasn't changed in itself although my perceptions of it might have. I'm still happy with the sharpness on the wider end, particularly if you avoid high contrast areas which will show up CA. The long end is still its biggest weakness for me. It's just that little bit too soft for my tastes, and never really feels sharp even after processing.
The lens does mechanically work on a full frame body, although the image of course doesn't cover the full range. It might be useful in an emergency, but you probably wouldn't want to use this normally.
My biggest gripe with it now is the zoom direction. The zoom ring twists in the opposite direction compared to Canon lenses. This was fine early on, as I didn't have any other twist zoom Canon lenses. Now I do, and am likely to get more in future. While I can adapt quickly to use either, I sometimes go the wrong way. When you have a split second wildlife chance, that is the difference between getting a shot and missing it, and I have lost chances due to this.
That last point is what's pushed me over. Time to sell it. Just got to find out how to maximise my return.
_________________Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.