Why don't you go to both? Rush for Rent - if you get there early enough you'll have a guaranteed $20 ticket. Buy some cheap seats to Color Purple.
So, that was the Drowsy Chaperone. Oh, I love it so much. I know it's not a perfect show...but it does what a musical is supposed to do. It takes you to another world, and it gives you a little tune to carry with you in your head for when you're feeling blue. Ya know?