I run both, half & half
Violets are Huge par monsters, they also will help fluoresce your coral some too. (think of uv light to detect urine stains; buy one of these flashlights of eBay & shine in your tank with all other light off & you'll be blown away by the colors!) Our eyes can't see the wavelength of light they put out so they look dim, but be careful in cranking them up too high or you burn your coral, put them on their own channel or if you run with the blue channel (I do), make sure you acclimate well.
For best coral coloration also use some Blue and Cyan. The tank you see in the pic is just a small 8 gal with one diy cluster that consists of 2 NW, 1L, 4RB, 2V (1V, 1TV), 1C, 1B. Also that is an old pic & didn't have the Lime, just got better with lime!
My new build has 4 clusters over a 30" light for a 36" tank. Trying to lessen the shading effect that is inherent with LED's as this tank will have more SPS. I went with NanoBox pucks because it was exactly how I was going to mix my colors(or very close to it). Plus for $55 an array, I almost can't buy individual led's for that price. Here's a link to my light build over on NR if you're interested.
http://www.nano-reef.com/topic/364364-diy-light-build-nanobox-edition-complete-photo-dump/