To be honest I haven't actually used it on a large app yet. I haven't worked on a Clojure project and I've only done small projects. However, my experience was good, the language is awesome, but when I was using it there was some pain getting it setup. I think that's better now.
See this answer for it's data-first model: hashnode.com/ama/with-james-long-cj5x0mut902fwjpw…
On top of that, it has a really powerful form of objects and protocols, which allow you extend and existing type but the extension is only locally scoped to the current environment. Think of being about to add a toNumber function to the JS String type, but it's only available in file that have imported your extension. It's like a safe way to monkeypatch; it's awesome.