I think 4th edition AoS will decide this battle. If its good, people will stick with AoS. If its terrible, people might move to the other game that uses the same minis, ToW or OPR.
Thats said, i expect Skaven to out sell Kruleboyz a lot. They seem popular and in need of a refresh since AoS happened.
I do hope to score half a starterbox for a good price. Might actually go for SCE. I really like them much more recently. GW really is trying to make them look different from marines.