Hey Dave

The main advantages are in the front shift - especially on the compact ring combos (50/34 and 52/36), the new levers and FD in combination with the new rings give a much better change, at higher torques, than do the existing lever / mech / ring combinations. We aren't allowed at this stage to give the numbers but having ridden it, it is noticeably different, with less effort at the lever, too.

Maximum downshifting torque and clean-ness at the higher torques is also significantly improved.

The improvements are greatest on the compact and compact-evo ring combinations, but still noticeable on 53/39.

We have a built-in system to stabilise the FD against the DT of the frame now, as well, to compensate for flexier seat tube walls and hangers that we see on many frames now, which otherwise tend to compromise front shift performance.

If you go with the 2014 chainset, because of the design of the FD you will still get some improvement but it's more a case of less force applied at the shift lever than clean-ness of shift as such. You'll probably end up trimming the FD a little more often, too, as the gate on the 2015 FD is reshaped and overall is a little narrower than it was in 2014, hence the chainrings are also a smidge closer together in 2015 chainsets.

At the rear, the RD wraps more chain around the cassette and is better at shifting in both directions at higher torques as a result. The redesign of the RD geometry and the FD gate also opens up the possibility of 11-29 at the rear - this used to be achievable on some frames with steeper seat angles and a smaller BB drop from wheel centres, where the frame had a hanger at the "long" end of Campag's tolerance, now it's possible on all frames that follow Campag's general frame compatibility spec (which is as close as anything ever comes to "industry standard" ...).

Weight wise, group-for-group 2015 is actually ~30g heavier on average than 2014 but given that 30g is less than the specified allowable variation in production weight on, say, a 600g item, that's probably (in real terms) neither here nor there - the trade off against greater rigidity in the chainset and better shifting is seen as worthwhile.

On the chainset itself, we have one spider for compact and standard rings, so there is only one set of cranks to buy - so if you want to swap from 52/36 to 53/39 it's very easy - just a ring swap and a quick check on the FD settings, or if you want to go to 50/34, a ring swap and reset of height / stroke of the FD. The new FD setting tool makes this a really easy, quick job.

We don't have full pricing info for the US as you have a different retail structure to what we have in Europe, so I can't really answer the pricing question other than to say it's not a savage difference at the factory gate.

Hope that helps
GFK