I'm not a weight weenie, and for the record, I don't care one way or another between sti and double tap or their ergonomics. But I am more concerned about long term durability. Sram groupsets are across the board lighter than their Shimano counterparts. Where do these weight savings come from? The answer won't really sway me one way or another. I'll take which ever groupset that's laid in front of me, because neither would let me down. I'm just curious whether anyone knows about this.

P.S. please try to be objective, because I'm just trying to gain some knowledge. Things like "I got 40,000 miles on so and so... not a single hitch" won't really help. It would help a lot more to get feedback from those who know a lot about the nitty gritty, or who have used both brands extensively. Thanks