There's not much to say that hasn't been said. Basically this lens appears to be designed around image quality, period. In that aspect, it's design is amazing.
In other aspects it's weaker, but obviously that was the design trade-off.
To me, the weight was surprising, but once on a 5D with grip, it feels nicely balanced.
I think if you have good focusing technique, using the '*' button, you will get good results, I was able to get in focus shots at 1.2 right away (no all of them, but promising results), it obviously a knife edge your playing on, but not as hard as some may have made it out to be.
I was really surprised by the sharpness at 1.2 also.
The chromatic aberration and green fringing is a bit annoying, but you can work around that in post processing, the price you pay, I guess, for working at 1.2.
Bokeh is amazing.
I've found focus is somewhat slow, but accurate on my 5D, if you don't have enough light for focusing it is annoying that it takes so long for the lens to hunt from near focus distance to infinity and back, seems like an eternity, but in regular use the focus ring is traveling much less so at least I don't notice it much.
I guess there is a reason for focus by wire, but it's an inconvenience that you need camera power to retract the lens, since it doesn't have internal focus.
Rear element exposure is a bit scary.
That's about it, I love this lens, and can see keeping it for a very long time.