Sram apex v rival?

[Steampig]

Been looking at a new roadie and i noticed the same bike comes with either Sram apex or for an extra £100 rival/105.
How much difference is there beteen the two Sram groups? would it be worth the extra £100, or more to the point is it stupid not paying the extra £100 (if i can afford) on £1000 bike for what is a better (is it?) groupset?
Answers on a postcard please?!?!

 

[Hacienda71]

IIRC Sram Rival has carbon levers Apex is alloy on the shifters and overall Rival weighs less, although Apex is still light in comparison to equivelant Shimano kit. The mechanics are the same with both groupsets.