SRAM have capitalized on the great success of their top-of-the-line X.O racing group by taking the same component shapes and using them to make their X9 group.
The only key difference is that where X.O goes the whole hog and uses carbon fibre for shifter pod tops and mech knuckles, X9 uses a tough plastic. There are a few small finishing differences but it's spit and polish rather than practical. You may be thinking: hold on, X9 isn't new; it's been around for a year... And you'd be right. However, up until now all SRAM groups have had to use the generic SRAM X-Gen front mech.
The X-Gen works well but is both bulky and heavy. SRAM have scratched away the unnecessary alloy, slimmed down areas like the band clamp and lost weight from the guide plates, thanks to a less than high-tech hole. Shifting performance on the new X9 remains excellent (the X-Gen was/is a great performing front mech); it just now looks more like it belongs on a top-spec bike.
We're still waiting for an X.O level front mech, as SRAM are claiming they'll only do one when they can definitively lose weight and increase performance. We say with the gains made by X9 over X-Gen by slimming the material down, there must be some parts that are able to be made of carbon...
