The Canson XL Mix Media paper comes in different sizes and paperweight. Note that the XL series also comes with one that uses watercolour paper. The reason why I bought the Mix Media one is because it is really affordable.
The size ranges from A5 to the humongous 18 by 24 inches. They are all spiral bound with perforated pages. Paper is acid free, treated to resist mould, except for the cardboard cover behind.
You can choose from 160gsm (60 sheets) and 300gsm (30 sheets). Main difference between the two besides the thickness and weight is the paper texture. On the 300gsm with coldpress and medium grain surface, they have this discernible parallel lines that run across the whole page. Those lines do not look good and when you use them with watercolour, it can be distracting. And those lines means that the paper is not good for dry media such as pencils or pastels.
From reviews that I've read, it seems that the 160gsm paper does not have this grain pattern, but that is thinner and buckles more with water.
For this sketch, I used pencils for the lines and water-soluble pastels for the background. The scanner was even able to pick up the paper grain texture.
The paper works very well with pen and ink. Strokes are sharp with no featuring.
The 300gsm paper handles water quite well. It does not dull the colours too much. It can handles some glazing as well.
The major downside of the paper is the obvious parallel line grain. As such, the paper is mostly suited for practice purposes, such as for mixing colours or casual painting. And it's affordable so it's quite economical to practice on.
Find more reviews at Dick Blick Art Materials (US) | Jackson's Art (UK)