Rasnov is definitely quieter and with awesome views of the surrounding area. I started early in Brasov, bus to bran and first in the castle at opening. I think both are certainly worth visiting. If you head behind bran castle there's a stream and an open field for good picture taking and relaxing away from the bustle. then just hopped off the bus in rasnov on the way back to bran and enjoyed the ruins high atop the cliff and caught the bus again back to Brasov. Nice full day trip easily done on your own.