RE: Spektrum 2.4 module in my 9CAP ?
I don't think you'll be able to find any "proof" that one is better than the other. I've never had any problems with spektrum equipment, plus there are BNF planes if that is something you're looking at. As you said there is a price difference, so much that trying the spektrum out isn't really much of a commitment, in fact only about $30-40 more than just a RX alone gets you the module as well, and then you're set!