I ran it about 8 years ago at low water, before the log got in there. It was NASTY. Almost pinned, and probably should have. Granted, I was probably in a New Wave Mongoose or such nonsense at the time, but I still think it's really too narrow to make it a "sweet" rapid- literally 2.5' wide down in that pocket at the bottom of the pic. I remember ricocheting off the walls and getting smeared on both parts on the channel.
It probably needs a good rockslide to fill in the creased parts of the rapid. It can be run, but I don't consider it a quality runnable rapid- especially when compared to others in that area. I've walked it since, although it's been a few years since I've run the Slate. I've heard folks say that with a good deal of water you can stay above the nasty stuff, but knowing that it's plumbed the way it is give me the the shakes. The fact that the banks are slick at glass for self rescue or extraction sucks as well..