Oanda is hands down one of the best out there. I cannot say enough good things about them.
I've placed thousands of trades through them at every hour imaginable and have nothing bad to say. In addition, competitive spreads compensate for any data feed glitch they rarely have.
The best part is that your stops are honored AT THE PRICE YOU SET THEM AT. That type of security is something that's worth a fortune esp when trading size with a system that uses tight stops.