* The correctable pens (fine point) can dry up pretty if uncapped. I had some case where my pen where partly dried and would randomly not write. In some case I had the feeling that a particular area of the notebook wouldn't let me write where in fact it was only a dry pen. You can "undry" the pen - see [1] - but the process is not as smooth and elegant as the video would suggest. I think it's less a problem with medium point pens; but I don't like writing stuff with those medium pens - too large to my taste.
[1] : https://youtu.be/y_PWw7G1jfg?t=51s
* While we're at it, the pens tends to die much quicker than a conventional ballpoint pen (2-3 month of solid use ? I don't really know). But then, I think I write more with this notebook than I ever wrote with a conventional pen, so my estimation is probably flawed.
* I think I had dirty fingers only once because of the pens, but then that tend to also happens with gel pens. Maybe there's something wrong with the way I'm transporting or holding them ?
* When you erase a whole page (probably with some water - the ink is water soluble - and a microfiber tower) and it is not properly and thoroughly dried, it can stick to the opposite page. But that sort of thing tends to happens to a lot of plastic sheets, and the leave are thick enough to not be a problem. It's only a minor papercut (... sorry, this pun was terrible).
* The spine is not supper-dupper rugged and I recently lost one spiral (one year after I bought it). But the perks of having reorganisable and easily scannable pages are worth it.
* I would really like dotted pages instead of lined pages but this is not available at the moment.
* OneNote OCR doesn't transcribe the scanned page as magically as what it can do with a tablet PC stylus (it's probably looking at the stroke themselve, something that is lost when you scan a page)