I am a firm believer in using the watercolor paper that you're more likely to use. Often times that means a cheaper pack so you can practice without fear.
 
That being said, there is a reason that 100% cotton paper is better. The colors flow together better, it's more forgiving to mistakes, and you have more working time before the paint starts to dry on you.
 
So if you've been looking to up your paper game, this is my favorite cotton watercolor paper. It's in a block form which is my favorite because you don't have to mess with all the taping down.
 
15 sheets
100% whtie cotton paper
300gsm/140lb
Coldpressed finish