2015 Retina Macbook vs. Macbook Air (early 2015)

Hi all, since it’s been long enough now for those of you who may have purchased a new mac, I wanted to ask again if anyone has a working opinion on either of the two machines while using Sketchup Pro.

Which model / processor? How was performance?

Deciding between the new 2015 13" MBA I7 -or- the rMB 1.2 or 1.3. Not sure if either will be better than my current rig (early 2011 macbook pro 15" 2.3, i7), but would like to know opinions on if either would be “close enough”. I travel frequently and the weight reduction could be nice… Any and all experience or thoughts would be appreciated!

you can compare the performance of CPUs here and of GPUs here.

CPU speed is most relevant (clock frequency not kernels), don’t overestimate the relevance of the GPU but even though do prefer a dedicated one instead of an integrated/shared version.