I've gone through one and a half of these bad boys-- the smaller book goes with ny to my 9-to-5-- and while they admittedly have a weakness to water based media. That's to be expected.
I'm terms of construction, it's held up pretty well to existing inside of my purse, and the cover feels robust and looks/feels good on its own without restricting me from making it tacky by slapping stickers all over it.
I'd say the biggest issue I've had so far is with dip pen and ink. The paper doesn't handle that level of ink without some feathering, so doing detail work with a g nib or blue pumpkin (or pentel brush) isn't gonna happen, but the paper doesnt tear from the dip pen.
Overall pretty good for the price!