This is a practical question.
I have done registration and login without using FOS. I finished email verification and password reset functionalities also. I managed to make
HWIOAuthBundle work and now I am able to sign up/login with social media.
I didn't use
FOS because I have two registration form and login form in same page and that looked incredibly complicated to achieve with
Since then whenever I was searching any solutions to any problems reffering to User management I usually see beautifull
FOS solutions. I started seeing that
FOS works fine with multiple bundles including
Should I rebuild my user system on
FOS and is it possible to achieve what I mentioned before using it? (2 registration forms + 1 login form in same page).
In my opinion, if you have the time, to make your own solution work as you intend it to, then stick with it. If not change to FOS.
Why not FOS in the first place? Simple: you have to overwrite/extend a shittone of stuff to make it work as you intend. In general, FOS User Bundle is a great bundle with a lot of functionality. But it has it's limitations and special things (like it requires every user to have a username and you have to either rewrite a huge part of it or use a quick and dirty solution like just overwriting the form and when the email is set set the username to the same).
I use FOS in several projects and it just works as advertised. If that's what you want, go for it.