To be honest I haven't had a chance to get out on it as much as I'd like. I've been working overtime lately and it's been dark by the time I get home. I'm usually confined to the weekends, but hopefully that changes in the next month or so.
If you bring your wallet on rides the Di2 would make you pretty light haha. I just picked up a Cervelo S2 last weekend, they hooked me with the sale. I'm hopefully going to upgrade to full Red over the course of the year piece by piece.