Missing from previous posts is any mention of the front chainrings contributions to the overall gearing. IMO a bigger front ring than the standard 48T is the ticket to lower ETA's but Fietsbob's observations have some validity. Still, I like to have a couple of big gears onboard when there is a tailwind, or when I'm on a downgrade (whee!!) or when the yellow signal is stale (!!!). YMMV.