...However, because of the required internal routing of the cables through a TTT Aeronova handle bar, my shifting was always somewhat compromised.
However, after going through two RD shifter cables in about 2500 miles, I decided I'd had enough of mechanical systems at which point I switched to E-Tap. What a revelation!
Not only is the installation straight forward and the adjustment easy, but the shifting worked flawlessly from the outset. I could reliably shift either up or down the cogs without hesitation or the fear of ghost or double shifts. It was also marvelous to be able to shift without backing off. My average speed and power output surged more than 5% from the simple expedient of being able to shift reliably whenever appropriate.
So, back to my original point. I'm thrilled with the performance of E-Tap and as long as SRAM honors their two year warranty, I'm a happy early adopter. With all the trouble I experienced with the supposedly great shifting Dura Ace 9000 gruppo and lack of durability with their shifter cables and cassettes, I know I'll never go back to mechanical.
To make another point, I now gladly carry a spare battery in my jersey pocket. I know I can switch the FD and RD battery if necessary, but since a spare battery only weighs 24 grams, has a volume of less than one cubic inch and pops into the RD in a few seconds, it provides peace of mind. It's certainly lighter and smaller than a spare RD cable.
Points taken @wootenlakeguy.... there are certainly times when electric (be it wireless or wired) is going to have its place for sure. In fact, I won't even build mechanical using a bar with internal routing if the bends are so tight and convoluted that it would compromise mechanical shifting. Or, I will just bypass the internal bar routing altogether. And yes, initial setup and getting things to "work as they should", is generally easier with electric it seems, particularly for less experienced installers. And for tt bikes, absolutely electric shifting, and wireless in particular saves a whole lot of setup hassles as well as providing for the placement of satellite shift positions. So yes, there are times when it's a great option. No question. The biggest trade offs seem to come when something just stops working as is the case here.
Apologies for the derailment. Hope the OP can get his bike back on the road asap and that down the road replacement parts become more readily available.