The megamix is good but I wish they didn't cut out Gaga's solo verse. It should go Rick Ross, chorus, Gaga, chorus, R. Kelly, chorus, and then the Xtina version for the rest.
US iTunes
27 Lady Gaga - Do What U Want (feat. R. Kelly) 0.2389
52 Lady Gaga - Do What U Want (feat. Christina Aguilera) 0.1672
0.2389 + 0.1672 = 0.4061, which puts it between:
11 Imagine Dragons - Demons 0.4344
12 Miley Cyrus - Wrecking Ball 0.3939
Don't give up hope

I think everyone expected the Xtina version to basically start selling instead of the R. Kelly version, but they seem to be selling concurrently at a stable rate, which is good. I'm still optimistic that it'll go top 10, which is the least it deserves.