I think Itoje was standout, but I think Launch showed better than Kruis.
Just checking the stats (I know they aren't everything).
G Kruis 3 passes, 4 runs, 0m, 0DB
J Launchbury 0 passes 11 runs 7m 1DB
Kruis made 13 tackles and missed 2, Launch made 12 and missed 0.
Considering that Wasps only made 90 attempted tackles (75 successful), and Sarries attempted 155 (made 123), Launch worked far harder with regards to the rest of his side.
Launch has really added to his carrying game recently, looking more powerful when he carries, and often keeping on his feet for those extra few yards. However, it may be that this isn't what Eddie needs, depending on the composition of the rest of the pack, and we know Kruis the better in the lineout.