Comparing Campagnolo and Rotor cranksets

So I have been using a Campagnolo Chorus compact chainset for the past year or so (2014 model) and it has 172.5mm cranks. This is on my 'summer' road bike. It works great, looks great and I've have been a Campy follower for a long time. For various reasons though I am looking into shorter cranks for next season. I recently fitted 170mm cranks to my every day road bike (a no-name inexpensive brand) and have a single chainring on there for spinning. I really like the change. I'm not really noticing that the cranks are shorter, but the pedalling actions is really smooth. Over the next few months I think I'm going to look at 165mm or 167.5mm. I have a feeling that 167.5mm is going to be the one. So this is where Rotor comes in. Thier 3D cranks come in with vartious lengths under 170mm. So, does anyone have actual experience with using both? I read a review of Rotor 3D cranks from a while back and they said that the cranks were good but the spider was not the stiffest and resulted in slow front deraileur changes. Does anyone know if this has been sorted out with the current range from Rotor ?

thanks,

K