Quote from SnakeEYE:
Let`s say if i`m interested in trading Eurex exclusively.What combination whould be more appropriate?
These three have global infrastructures and I think all three have their own direct connectivity to Eurex so all three of CQG, TT and Rithmic at least should be good choices.
Most of them have connectivity architecture details on their web sites that you could look at. I am sure you could have a whole thread on which is best for Eurex (or any other particular exchange).