Reflecting on the
MGMAT booklet, here are some insights I took away from using it that may be overlooked if you're still considering to study with it.
1) Use the booklet horizontally. It won't get in the way of the keyboard, or you, for that matter. You may actually like it better that way.
2) You'll discover (or rediscover) if you write big, and set yourself to train to write smaller. It's better to get used to writing smaller now than on test day!
3) You'll learn that if you write in an unorganized manner, the amount of space you waste is much more noticeable, because you may find yourself consistently moving onto the next clean page. This may sound like it's not such a big deal, but the booklet doesn't give you an unlimited number of pages - far from it. There are only several (10 or so) pages so staying organized matters more than if you were to practice on paper, which you may have more of to work with while practicing. Training yourself to be more organized may mean less time wasted waiting for a new booklet.
4) Don't write as much - at least for the verbal section. If you're able to do questions without writing, that's a good sign of where you're headed. This one you probably already knew or realized while writing on paper, but the less you write, the more time you have to read and think. I've personally realized how much I don't look at my notes for the verbal section.
EDIT: that is, if you write too much and your notes aren't efficient, don't write as much. Learn to make do with less and utilize efficient shorthand.
5. If you like writing with bold or gel pens, the test day marker will annoy you. Get used to it since that's what they'll give you on test day. It's an ultra fine point 0.4mm tip that sometimes doesn't write well if your writing angle is off. Not to mention, the marker may run dry while you leave it uncapped, or it may have dried out from the last test takers who used your marker.
Also, remember that these are not dry erase markers - they're wet erase. They both erase, but one comes off more easily with water, so you won't accidentally smudge it off (as much) - learning how to interact with something as minor as how the wet erase markers work may be something that'll make you more comfortable.