Justin There is a main difference though.... One is open source and thus code can easily be audited, the other adds some proprietary blocks and has a business model largely based on leveraging user data.
So I fully agree that Mozilla is not perfect and doesn't always take the good decisions nor is always as transparent as it could (silently enabling some features for testing without the users knows unless they visit their blog), but what @3ImWeckla claims is just misinformation (fake news as would scream a guy with a ridiculous haircut) based at the best on some inaccurate info.
Also the option "Allow Firefox to install and run studies" which is one of the main criticism, is not enabled by default in Solus.
People quickly forget that Mozilla invest lot in privacy protection, they organize campaign, educate, sponsor many projects and they are the last offering an alternate engine to WebKit/Blink. So free criticism based on some nothing serious at the best or on lies (Mozilla finances & privacy chart are public and much easier to read than the ones of most other companies) are just harmful and would just help damaging the only alternative to the web engine monopoly.