I absolutely love my Northbooks journals! I use them as project journals, which means I reference them continually, long after they are filled, and these are sturdy enough to hold up to that level of usage. They also don't break the bank, so I have more creative freedom to do experiments!
I write almost exclusively with fountain pens, and these notebooks work like a dream! There's little to no show-through, even with a gushy liquid pen, AND they dry quickly so I don't have to wait a while before I turn the page. My brush pens and markers that I use for decorative headings also work great. These are FANTASTIC notebooks! And I absolutely love that they are Made in the U.S.A.!!
Also, Excellent Customer Service: One of the notebooks I received was mildly damaged in shipping, and Northbooks really went above and beyond in their response. They sent me a new notebook at no charge, and were great to communicate with. This is a fabulous company--I highly recommend both their employees and their products!