The good people over at Cycle EXIF know their bikes. They've been riding around on a Parlee Altum equipped with SRAM eTap for a while now and have just published their review.
"In use, eTap is fantastic. There's no feeling around to check you've got the right button (occasionally a problem with Di2) and you can quickly and easily tap either shifter with any available finger (not an option with EPS), which often saves from having to move hand positions regardless of shift direction. The button touch is light enough that you don't need much force to activate it but firm enough that miss-shifts aren't an issue."
Read their full review HERE.
UPDATE: You can read our latest thoughts on SRAM eTap HERE.
"It was so enjoyable to use that I sometimes found myself shifting just for the hell of it!"