I haven't tried Di2, but I do know this: Chris Froome has his bike tuned up every single day by a professional bike mechanic. If that's not good enough, he has a van following him around with an identical back up bike all ready to go with it's front wheel already installed and tires pumped up and ready to go. During the Tour De France one topic of discussion was whether the peloton was right in holding up while he changed bikes because his Di2 shot craps. I wonder how many additional times that happened to riders who didn't happen to be the race leader and consequently attract a lot of attention.

I'm thinking that it's probably really, really nice when it's working right but I've lost patience with unreliable electronic gizmos. If that makes me a retro grouch, I'm OK with that. Given the choice between reliability and features, I'll pick reliability every single time.