Polaroid Sharpness Question

Piggybacking off of a previous question...

I always make my own polaroid brushes/templates because I can then customize them to whatever size or color I may need/want. The problem I have is the edges look nice and crisp when created, but then when I try to rotate them (Whether it be through "Rotate Image" or "Free Transform" or any other tools) the edges turn pixely.

Nice crisp polaroid brush before rotation.

Pixely border polaroid brush after rotation.

I tried playing with the sharpen and blur tool and neither make it look any better. To make the polaroid I'm just using the rectangular marquee tool. Any suggestions on how to get a nice crisp border after rotation?

ETA. I'm using Photoshop CS