The fact that W&D - which is not eligible for C2C and has historically not been a super fast seller - sold out so quickly makes me think MW may be just as fast or faster. And that fast sellout means a LOT of people on a lot more devices waiting in randomized queues, which seems to result in more people getting shut out. I’ve been doing these things for more than a decade and I was surprised by how messy W&D was this time. I still had one device saying “more than an hour” wait long after everything sold out. (Two other devices did get through, but neither as quickly as the queue URL a DISer gifted me - and I’m pretty confident I’d have been shut out of either the Challenge, the 5K, or both, had I waited on my own original queues.)
My beef with rD’s system is that no matter when you enter the queue, your place in it seems to be randomly placed: being quick on the draw does not mean you’ll also get a short wait in the queue. I know people who didn’t even try to enter the queue until 10:10 and got through faster than I did at 10:01.