Started a longer post on this last night but I guess I never finished it so here s a more succinct version. Having read reports about the Rey and Kylo in this wave being "upgraded" versions compared to their previous releases, I bought one of each yesterday to compare. I didn't see much difference in Rey frankly, the lipstick paint apps are slightly lighter and more delicately applied, but that's about it that I can tell. I like the newer version but I don't really regard that as a legit variant, just a subtle tweak.
Kylo however, has some pretty notable differences from the first version. They added a red wire painted on his lightsaber hilt which was not on my original version, and the texture on his cowl is completely different from the original one. Hard to describe without seeing it but it has a sort of "gooseflesh" texture where the first time around it was much smoother like a crumpled towel. I think they also slightly changed the cut or length of his robes too.
I decided to hold on to the extra Kylo since the changes are fairly significant in my mind and I like having both.