I've heard of the coinbase delays, but I've never experienced them, though I haven't tried to sell during a major sell-off or buying frenzy.  When I have used them, they've been great, fast and easy, no problems.  I guess I'm just lucky, cause I see a lot of people that don't like them.

I do think they've been a bit better recently, just from the amount of people posting positive things about them.