Give me one reason why should I go for an MBP 15 retina

I am pretty much imperssed with the 15 inch MBP retina. After using iPads, I don't find Apple OS any way suprior or inferior to Windows, but different. Yes the GUI in Mac good (maybe because after working on Windows, I find it different, therefore excited) and the number of applications available in the store are amazing.
But over my existing HP Envy 15, how will an MBP 15 be helpful to me in terms of.
1) Productivity
2) Entertainment
3) Education (I always carry my laptop in my MBA classes and...

Give me one reason why should I go for an MBP 15 retina