Actually I was wondering if people ever switch their crystals once they have their favorite. I know that when I grab Russan, I never switch to any other. The added lightsaber damage, blaster bolt deflection, added lightning damage, damaging aura, and Katak never see the light of day again.
I also never switch to any other color than green, which is why I hate that it is so far into the game before I can find it. I just hate how if you don't like red, you get unstable red, and then compressed red. You hate yellow, you get U Yellow, C Yellow, gold, U gold, and C gold. Nine crystals which are essentially only two colors for much of the game before you finally get some variety late in the game.