Never, it's fantastic. The monkey patching just adds context switching in all the right places, like IO and sleep. I've been using it for the better part of a

Never, it's fantastic. The monkey patching just adds context switching in all the right places, like IO and sleep. I've been using it for the better part of a decade and it always just works. A few C libraries are not compatible, like mysqldb, but there are alternatives and workarounds. The entire standard library works perfectly as far as I can tell.