I have a part time job in one of the LGS here, and I can vouch for 100% magazine interchangeability between the PCR and the Shadow II Compact Carry.
As far as the differences between the 2 (PCR/II Carry).....yep, very much on point with the "busy" comment, and the PCR seems to be a bit slimmer in the hand, lighter feeling to me and others comparing, but lacking the rail and red dot interface if those 2 are necessary for your tool choice.
I have a set of VZ panels on my PCR, and a set of XS sights, the only mods to the CZ, and I much prefer that to the Shadow II compact Carry. The PCR is more svelte in the hand, and a joy to carry.