With MaxCDN in the loop, we had random failures from various areas, and their support was rather anemic. Their UI had bugs which made our zones uneditable, and the whole experience was slightly better than nothing.

I've replaced it with a Ramdisk cache for my assets, served out of nginx, and it performs -dramatically- better.

Granted, that won't be possible for all workloads, but for me, it was a dramatic difference.