He's also one of the preeminent minds in quantum computing. When Scott speaks he's worth listening to regardless of his mannerisms.
What's annoying about him? I didn't notice anything annoying.
I find it is the same with his writing. It just goes on and on. His more technical papers are better, but his blog is just a pain. I guess it takes more work to be brief. (At least for some.)
Personally, I find his writing style very enjoyable and often hilarious.