Originally Posted by Sutra
...The Artistico is 100% cotton where the Studio is only 25% cotton. My guess is that this is less important for colored pencil, especially if you use it w/o solvents, than when you use those liquids or watercolor...
The more cotton fibers in a paper, the longer it will last and the better it will hold up under drawing. If you're just doodling, you don't need an expensive or archival paper, but if you're doing something like portraits for others or if you want to create gallery-quality work, you definitely want something that's going to age well without yellowing and deteriorating.
As for using watercolor paper for colored pencil: If it's archival, it should take pencil quite well. The real question is going to the method you use. If you like fine detail and a lot of "polish" on your drawings, watercolor paper is likely to be a bit too rough.
But if your style is looser or if you incorporate wet media like watercolor or acrylics, watercolor paper is likely to suit you well.