ColdFusion/CFML. All day, every day. Although a heavy dose of the newer hotness and the eventual migration of everything I work with off of it is in the works. Still enjoy working with it though. Very productive.
I still maintain a ColdFusion based site and am looking into building a new project using Mura. It's actually a fantastic CMS both from a developer and non-technical user perspective.
A lot of what's being built today as "web first languages" has existed for a long time in ColdFusion already for over 20 years.
ECMAscript style coding support that unlocked the underlying JVM in its entirety is one of those things.
It was one of the first, and only languages and platforms that was made for the web first, instead of extending non-web language to the web with a framework.
A mess can be made in any language :) Be scared to see what today's modern frameworks and their code bases might look like in 10-15 years, because some projects will have that lifespan.
The only real mess is the project's continual struggle against the language's verbosity and limitations. I try not to think too often about how much shorter some section of code would be if it were in Flask or Django.