I don't think it took up space at all but I love "order" with my stuff so I preferred the organizer for the MM one. It's the 2mm felt one however.....it does give it a bit more structured shape vs soft. Hope this makes sense so my elbow probably stuck out a tad with it. No.....I did not think it had any slouch without the organizer. I am just one that needs some order in my bags so if that is not a concern then don't order one. Honestly, I would live with the bag for a bit before you decide on an organizer at all. You will love the outside zip pocket and zip top! I'm thrilled with it!!!!