https://blog.torproject.org/tor-is-still-safe/
Tor is still alive and well I promise
It is not perfect but it is by far the best thing we have. If it's legal for you to use you should be doing so.
For sensitive operations you should take further steps (follow the blog) like properly setting up your device, and connecting via a network not connected to you
No, they're not the same.
Tor browser gives you ANONYMITY, which is not the same as privacy.
What is Anonymity ? Why is it Important ? http://blog.nowherejezfoltodf4jiyl6r56jnzintap5vyjlia7fkirfsnfizflqd.onion/opsec/anonymityexplained/index.html
Why isn't privacy enough for anonymous use?
http://blog.nowherejezfoltodf4jiyl6r56jnzintap5vyjlia7fkirfsnfizflqd.onion/opsec/anonuse/index.html
(BTW stock Firefox is not even private at all)