To be honest it is very tough to identify a True ECN broker. But I have experience trading with few ‘ECN by Association’ brokers like FXCC. I have had experience with them multiple fake candles! I have screenshot.
First point is, a scam broker won’t ask you twice for verification but Tickmill ask me twice to send my documents. I had to provide my Passport and rejected my ID card! (No FX broker did before, I have open account with more than 20 brokers with this ID card!) They wanted a paper scan (after providing the digital pdf)! I believe this is a great sign.
I traded the rumor of today (Trump threaten N.Korea) , I had 4 short at USDJPY and all of them was close in positive slippage! ( one of them was 3 pips), Nobody does that unless a true ECN. Never found re-quote! And you can set SL anyway you like no minimum PIP requirements. And they offer no big offers which is a big sign of a good ECN broker.
Hope this will help newbies. Hope they will ignore those broker who offers so much free stuff.