Any thoughts on the relative merits of the SRAM version?
SRAM/Shimano/Campagnolo is purely down to personal preferance. Some people like the hoods of one over the other (shimano 6700 are quite bulky, Di2 and 6800 less so, SRAM and campag are also pretty compact, especialy campag). Some people can't get on with or don't like some shifters, Shimano have a flappy brake lever for downshifts and a little paddle for upshifts, campag use a similar paddle but for downshifts and a little button on the hood for upshifts, SRAM use one lever, tap it to upshift, push it to downshift.
Any preferance you have will overide any value for money considerations, unless you're a weight weenie, in which case SRAM Red is significantly lighter mostly on account of the double tap internals being a simpler design than the Campag or Shimano solutions..