You may have to experiment and conduct your own research on this. Interactive Brokers is pretty tough to beat but you may find limited choices in terms of Forex CFD's pairs to trade but sufficient American pairs. You won't beat the commissions though with IB. However, one of the cons of using IB with Motivewave is the prerequisite of having to start IB Trader Workstation or IB Gateway first and then the Motivewave platform, a potentially cumbersome and bogging down process.
Forex.com in contrast is a well known broker with a dedicated broker connection directly into Motivewave via GFX. Once connected, you just open up the Motivewave console. The Forex pairs available are similar to IB but perhaps one of the cons is the complex terms, conditions to satisfy and documentation to submit.
