Originally Posted by
Malloric
The holy grail is of course Dura-Ace Di2. Never ridden it, but I've watched people shift it while sprinting on a trainer.
That's an amazing engineering feat; no other groupset comes close. There's a bigger difference between Di2 and mechanical Dura-Ace than there is between Sora (lowest end) and mechanical Dura-Ace.
I was going to mention Di2, too. One of the recent posts about it said that they've actually programmed the front derailleur to shift at a certain point in the crank's rotation, pulling the chain exactly onto the pins that guide it onto the teeth.
That's the only groupset I've heard about so far that lets the front shift under heavy load. I remember how much people were talking about it when it debuted on the bike trade show circuit (probably Interbike). They all tried their hardest to make it misshift and it never failed.
I still softpedal on shifts, though; DA/Ultegra on one bike, flatbar Tiagra on another, Sram MTB group on a third.