First, let me say that I have a very large collection of pens. Depending on what project I'm working on determines which pen(s) are used. Because of this, I am always looking for pen holders and organizers that make it easy to categorize them and separate them to make it super easy to find the one(s) that I'm looking for at any given time.
This is the first case that I have found where the inside inserts are removable. This is a huge benefit because if all of one type of pen fits on one insert, I can easily remove that insert while using those pens and move the full case off my workstation. Since they are velcroed in, this also give me flexibility in where they are placed in the case. Since some of my pens/markers are thicker than others, I have the ability to give the thicker ones more space between inserts and less space between the thinner ones. This helps with fitting more pens in the case - which usually wouldn't be possible if they inserts were not removable and adjustable.
Most likely I will be ordering a couple more of these in other colors to help color code my various pens by either type or use. The features of this case are just too great to pass up and this case is definitely better than some of the other options I have tried.