I'm chiming in, wow what a voice, fantastic singing on this track. Four-on-the-floor sounds great. I listened to it on my bassiest headphones (770 Pro's), so I think I heard it in its intended sonic context, where there's plenty of bass.
I'd like some more mix contrasts throughout: when the harmony singers join in, I'd like more of them, for example. On first pass I actually missed realizing they were there at several points. Switching from a very lead-vocalist sound to a true ensemble-of-us-singing-together sound would work very well.
It might also be effective to put some additional variety in the bass drop, when it happens. You've composed the drops just right--now I'd like to hear a little more difference every time. Get together a really huge one for coming out of the bridge.
I realize the original post is just asking about mastering, so I apologize in advance for veering off into other areas. Mastering wise it's very close. With the lead vocal sounding so good at this stage, I'd say a very very light touch please on whatever tweaks are made.