Black and White or Color?

I recently read an article about how to take good black and white photos, and it got me thinking. Back in the dark ages, when I learnt to use a SLR, I shot almost exclusively in black and white. Mostly because I had to for assignments, and it was cheaper if I had free access to the chemicals for developing film myself. Also, I had some bullshit idea about it being more artistic. These days I shoot in color, but occasionally take a photo that works just as well, or better in black and white.

I took this pic with my iPhone 6. It works great as a black and white because the focus is on the structure. I feel like it also enhances the contrast to create a more dramatic image.

I took this photo with my Canon 7D DSLR. I used a polarizing filter, thinking that it would enhance to red rocks. It also darkened the sky and the details really pop.