The Ultegra bike has the C2 seatpost (C2 seatpost is carbon C3 is aluminum wrapped in carbon) but both have C3 handlebars. Obviously the cranks are different but depending on who you talk to either one is better. The SLK light on the untegra bike is really nice. Also the brakes are much better on the Ultegra bike as the Rival bike has generic Sram brakes not the rival line. Kind of like how the 105 version has tektro brakes and not 105 brakes(I have the '12 10-5). Just upgrading the pads alone would fix that to an extent.


Also wheels are are about the same level on both. Not stellar but easily can upgrade later to somehting like the Boyd Vitesse wheels and sell your stock ones for $100-200.