I was at MesosCon 2015 and watched Verizon start 50,000 (yes 50k!) containers on a 1000 physical node infrastructure using mesos in 73 seconds. If you're just going for speed of launching, that is pretty snappy :)

http://www.techrepublic.com/article/verizon-puts-50000-docke...

Nice side-by-side demo at http://force12.io

very clear