I had a problem with GFT recently which lead me to close my account. They filled my orders differently to other clients.
The strat i was using was very agressive, a stop entry with a contingent stop placed as close asp to the entry. One morning i started to experience consistant slippage rather than just the odd one or two so phoned to enquire what was happening. I was told that the slippage was as per tick (which i do agree with) but they denied that anything had changed or that i was being singled out for special attention (which i thought was BS and the point i had issue with).
Anyways, with the help of a member of T2W we proved that i was being treated differently (we put in the exact same orders at the same prices / same times). Mine were slipped and theirs were not. I phoned back and talked to a back office manager. He looked throgh trades and said that i was very agressive (which i was), that i was scalping (which i wasnt), that i was trading latency (which i wasnt if take it to mean trading a lagging or frozen price). The conversation got heated when i explained id got someone to mirror orders and we were filled at different levels!
The way i see it is this, you are one of three types of client:
1) one that loses consistantly.
2) one that wins but can be hedged.
3) one that wins but cant be hedged. (this would describe my trading with GFT at that time)
1 and 2 are fine, 3 is a problem. Id see like this if i were running the outfit.