Since Joomla 2.x, it supports memcached out of the box. It is simple to use also. You just need to switch the cache handler to memcached after you have installed it on your server. It is working pretty well for small websites with moderate traffic.
However, we found that memcached is not reliable when it comes to a big website with a lot of contents to cache. It makes the website slow especially when you have components as some do not play well with memcached.
We also tried to scale memcached by splitting memcached into multiple servers. Unfortunately Joomla does not allow multiple memcached servers. I did ask about it on Stackoverflow and this is the only answer I got http://stackoverflow.com/a/38262046/359034 which says it’s in the code but you have to tweak the core. I rather wait for official release than modifying the core.
We have struggled for a few weeks. Finally we gave up and went back to file cache which performs way better than memcached in a long run.