MB or FastBrokers?

I need an ECN broker, and the only reliable ones I could find that had minimum ECN initial deposits to open the account are Fastbrokers and MBT.
I am on the fence. I like Fastbrokers and MB, but not sure which one I should go with. If I go with MB, I get 25% of my commissions back from a promo.

Anyone have any experience with these brokers? Which one I should go with?