There is no doubt about it that Mozilla has improved the Firefox web browser a lot ever since it switched to the rapid release cycle. I'm referring to performance and web standards improvements first and foremost.
There is also no doubt that Mozilla made several questionable decisions in that time as well. The controversial launch of the new Australis interface in Firefox 29, announcement that the organization will integrate Encrypted Media Extensions (EME) into the browser, or that it will display sponsored tiles on the browser's new tab page.
Mozilla has been criticized for all three of those decisions and it is likely that at least some users made the switch to another browser as a consequence.
One of the alternatives that gets mentioned regularly is Pale Moon. The Firefox spin-off is available for 32-bit and 64-bit versions of Windows and for Linux.
It is not just a simple rebuild of Firefox though. This becomes apparent when you try to find the three features Mozilla is criticized for in Pale Moon.
The short answer is that they are not part of the browser. The author of Pale Moon confirmed previously that the web browser won't switch the interface to the Australis design but will keep Firefox's original layout and design instead.
The most recent Pale Moon version available at the time of writing looks similar to how Firefox looked before Australis landed. The only real difference here is that it displays a Pale Moon button instead of a Firefox button.
The author of Pale Moon confirmed on the official forum that Encrypted Media Extensions and sponsored tiles won't be included in the browser as well.
While it is understandable that sponsored tiles (ads) won't be included as this is a Firefox exclusive feature that Mozilla uses to generate extra revenue, EME requires some explanation.
The author noted that Pale Moon won't implement DRM including EME or Adobe's closed-source encryption module. The decision will affect Pale Moon users who are subscribed to streaming services such as Netflix. While it may be possible to integrate support in form of a plugin as suggested by the author, it is not clear if such a solution will be available.
If not, it means that Pale Moon users will have to use a different browser to access streams that require Encrypted Media Extensions.
Pale Moon's attraction increases with every controversial feature that Mozilla implements. That's not a bad thing, considering that you get all what makes Firefox great if you install the browser.