Yeah, I have been out the last two days on 100km, and 140km rides, and the shifting has been perfect both days (well, apart from missing shifts because my fingers have been shaking so much in the cold...lolz).
Ultegra 6870 vs. Dura Ace 9070 front mech, observations;
-9070 seems to give more of a solid shift, if that makes sense. Ultegra is very good, of course, but it doesn't seem as powerful.
-6870 takes slightly longer to auto-trim when shifting about on the rear, and also when downshifting it takes a bit longer to auto-trim if done in combination with a shift up the cassette, to the largest cog.
-6870 cage is more 'basic' with none of the 3D design that the 9070 has. This is perhaps where the difference in shifting feel comes from.
-Not sure if this is specific to me, or what it really means exactly, but the 6870 front mech needed to be adjusted out to +9 to be at the same position that my now-dead 9070 was, at +2.
-The 6870 doesn't have a screw on the cage to open it, meaning you have to split your chain to get the mech off (or use a split link). Bit of a pisser that, as it meant I had to split my chain to install, and now have 2 pins in my chain. Not a massive issue, but they could have put a screw in there, like 9070.
I have never used +9 at my UL 6870.
I don't know if it has to do with what BB you have?
I have the wide BB 386EVO (Open Cycle UP).
I was also told, the servo inside UL and DA is actually same and battery is also same.
So in theory, none of them should be stronger or weaker?
I still wonder how 9150 will be differnt compared to forthcoming UL.
Just looking at shifters, now it seems DA has it's own 9100 series shifters (9150 mech/9170 hyd) name instead of 785 which is used for both 9070 and 6870.
Frankly it seems the 6870 is best price/ ratio now.
9170 is crazy expensive!
Off topic for road bikers perhaps, but Sram Etap FD has no battery clearance for gravel bike tires over 34-35mm.
I currently ride 42mm tires which almost gnaw my seatmast tube at my UP.
The clearance to UL FD, is better than the frames clearance.