It works in all the ACS 4.X distribs and remixes that I've seen. A funny is that it seems to compile each of the first five(?) runs, and cycle through them when you request a page, so if you have a bug in the compiled ADP that can vary per page load, you'll get some REALLY confusing behaviour. This happens mostly when you're trying to overload tags in the request processor.
Overall, it's a fantastic feature -- many pages load about 10 times faster once compiled.
