It's a great pen, but don't get the polycarbonate one. I got one during the Kickstarter. It writes really well, but the material started breaking at the bottom of the cap. I've emailed the proprietor multiple times and gotten no response. I think it's just the material, so probably any other material he has would work well.
Send me an email at will@tactileturn.com and I'll get you a new cap. I got some time to redesign the polycarbonate caps at the end of December to add more material to the bottom of the polycarbonate caps and it has fixed the issue.