How many of you guys mix multitracks?

I just discovered these and imo mixing them is THE BEST WAY to practice mixing. The reason why is because you don't need to worry about trying to write/arrange/compose the song at the same time since it's already laid out for you. If the song sounds bad then you KNOW it's because of the mix.

This website has a bunch of multitracks that are useful for practicing. Just thought I'd drop it here for those who may find it useful.

http://www.cambridge-mt.com/ms-mtk.htm