I didn't think much of Aaliyah when I punted with her. id say Harley has a bigger ass PP, but I appreciate you might enjoy Aaliyah's ass more.
Although I wouldn't be keen on Alliyah in the civvie world I agree she is slightly more attractive than Harley. I'd chose Harley over Alliyah without hesitation personally, as I punted her last night and will probably go to see her again before she takes a break.
Aye my learned friend

- even if I would choose both

With regard to bum per se although Harley's bum is round, the enormous size of it means it is
harder for it to be 'spherical', whereas Aliyah's is slightly smaller which means it comes closer to being 'spherical', and the true definition or as close as possible to the definition of a 'bubble butt', if you follow?
Out of interest why would you not be keen on Aliyah in the civvie world?
Cheers!!