I had something else written entirely for this, but I'll give you the bottom line up front: this is a really weird pen. I wanted to love it: it speaks to the "man" side of me with the rulers and level and driver set. But the size is just slightly too small, the way the nib eventually twists around in the body is uncomfortable and weird causing you to adjust your grip every few minutes which is terrible with a non-smooth tube for the body, and the fact that you have to have a special sized refill for it just killed it for me. Maybe this pen works for some, but for me its just WAY too much going on on one pen.
Disclosure: I got this pen for free in my monthly ink sub box; I did not pay for it. The review is my personal opinion on the pen. The ink was great btw!