On the exterior of the pen, there are several machined grooves that add nice visual separation along the length of the pen, and the grip section has several grooves that make it easy to grip the pen when writing. These grooves don't have sharp edges, making them very comfortable and secure when writing.
The clip on this pen is exceptionally strong, which makes sense after reading that it's made from machined stainless steel. It's not difficult to slip onto a pocket or bag sleeve due to the generous angle of the clip opening. Once you've secured this pen to something, it takes a good amount of force to move it. I have no doubts that this pen is staying right where I put it unless something underneath it pushes it straight up and away from whatever it's clipped onto. So, it might not be the right pen to clip onto your jeans when doing maneuvers that require lots of agility.
But, even if the pen does go for a tumble, it should be just fine due to the aluminum material. The pen is still lightweight, but the aluminum material makes the pen feel very solid and high quality. I'm sure it will take on lots of micro-scratches over the years, and I look forward to that worn-in look it will surely develop.