The first 2/3s of Seveneves were pretty good. I think you can reasonably skip the last 1/3 of the novel. Anathem is definitely his best written work. Don't bother with REAMDE.
REAMDE was interesting to read when it came out as it had many ideas about the very-near-future that had yet to come about but are now true. One was how malware will grow dramatically in frequency and sophistication once there is an anonymous way to pay the criminals online. Written before criminals started using Bitcoin. I would agree it is now not worth reading unless one just wants to read everything by Stephenson.
Yeah, agree. You'll reach a point where you very obviously know you can stop.
I sometimes don't mind his "explain every little detail of the physics of how things work" style of writing, but when that's the majority of what you're reading over several pages of being introduced to new characters, it's a bit much.