Okay, am getting fed up waiting for a certain northern on-line retailer to restock the SRAM PG1070 cassette so am wondering whether I should just go for a Shimano Ultegra instead...am looking for an 11-25. I'm running a mostly SRAM Rival drivetrain but with a SRAM Force rear mech. So, what do people think about Shimano cassettes versus the SRAM ones and am I right in thinking that I may have to remove a spacer if I'm to use a Shimano cassette? Both my (rear) wheels are set up for SRAM and I believe one or the other requires a spacer? Any thoughts. Second question; I'm getting fed up waiting for a certain northern on-line retailer to restock the KMC X10 EL chain and am looking for alternatives. Any suggestions?