I use the cards for notetaking. Thickness is important so that it does not become folded in my pocket. I use them to write scripture on for memory too. The lined is better for that.
Unfortunately you can't get good quality 3x5 cards any more. I've gotten them at Staples [...]the local drug store stationery stores you name it and in the last five years the paper has gotten [*] The cards used to be stiff enough to file with ease (no bending) and they had a surface that kept ink from flowing through to the other side. It makes no difference what brand you get! They're all the same. Staples at least should look into improving the quality of ALL their index cards. THEY SUCK!Note: I recommended the product only because it's all anybody has!