I adore cc. Some of it can look very poorly done, but for the most part, the simming community is fabulous about creating really awesome custom content.
It really helps me to have options. Women love our options and I get bored very easily so to have the ability to choose from 100 hairstyles rather than 15-20, or having the ability to choose from 300 outfits rather than 100 is really fantastic to me.
There are so many unique things out there for The Sims. I saw that someone had created a giant Bath & Body Works store filled with real BBW products in it that could be sold in GTW.
The creators of cc are so talented and personally, it does NOT slow my game down and my origin account updates my game automatically for me but I never remove my mods. Havent had any issues thus far.