Which Forex broker do you use?

I've been with Darwinex for a few years now. It's excellent for validating your trading results. You might even find some flaws in your strategy this way.
And if you are profitable over the long run, you might even find some investor to invest in you :) Definitely worth taking a look at them. They are regulated of course and I never had any problems withdrawing money.
They are my third broker so far and I'm pretty sure they are going to be my last because I am very happy with them.