I had no trouble with my Futaba S3003 and Associated S1903MG servos when I popped a Spektrum 2.4 unit into my touring car. I've also had no issues with the Futaba and JR servos in my airplane getting along with that same Spektrum 2.4 unit.

99% of servos on the market today don't care what modulation you use, nor do they care about the brand of radio. The receivers all send the same signals to the servos, and while some may move backwards in relation to others they'll usually work fine.

As far as the brand goes...it doesn't matter so long as it's a name brand. I'm a Futaba fanboy myself, but I've had absolutely no trouble out of my Spektrum DX5e and AR6110e combo, which I'm using in my touring car. I plan on stuffing an AR600 into my trainer here real soon and using the same DX5e on it.