I've been using PageSpeed in production for over 3 years. It's definitely not a replacement of manual optimizations, but in some use cases, especially when you don't have full control over the generated assets (such as third-party WordPress plugins), it's better than trying to fork those, or do transformations in PHP.
It requires you to get how it works, the specifics of filters, and so on; it's not so user-friendly, but once you figure it out, it's performing great. Also, the lead developers are very friendly and responsive!
One of them (Otto van der Schaaf [0]), who's not employed by Google, ported PageSpeed to both IIS [1] and ATS (Apache Traffic Server) [2]. I greatly respect Otto! He's such a hard-working, friendly, and dedicated developer! Jeff Kaufman [3] is also an amazing talent!
It requires you to get how it works, the specifics of filters, and so on; it's not so user-friendly, but once you figure it out, it's performing great. Also, the lead developers are very friendly and responsive!
One of them (Otto van der Schaaf [0]), who's not employed by Google, ported PageSpeed to both IIS [1] and ATS (Apache Traffic Server) [2]. I greatly respect Otto! He's such a hard-working, friendly, and dedicated developer! Jeff Kaufman [3] is also an amazing talent!
[0]: https://twitter.com/oschaaf
[1]: https://www.iispeed.com/
[2]: http://www.atspagespeed.com/
[3]: https://plus.google.com/u/0/+JeffKaufman