I received this pen as part of a birthday gift a couple of years ago and haven't stopped using them since.
The defining feature of this pen, in common with the more expensive and original Space Pens, is that the refills are pressurised and that allows the pen to be used to write against a wall, or even upside-down. The pens can take a bashing and keep writing. The clip is really useful for me as they can clip on to my scrubs or lanyard. This pen has continued to function perfectly throughout and can probably survive a lot more abuse other than being crushed! The pen can be refilled with new ink.
The Price is one that you don't want to loose but isn't the end of the world if it is misplaced.
Part of my on call essentials
Dr Kevin Rafferty