My current pencils in use are a Pentel graph 1000 for pro in .3mm which is my top choice. Then I have a kokuyo enpitsu in .9mm which is very cheap and comfortable to use, and a Sheaffer twist mechanical pencil thing that is just really fun to use and has a nice heavy metal body.
I can't say I would choose any of the above pencils, I don't even see any lead holders (clutch pencils)!
When I was doing roofing the pica dry mechanical pencils made things so much better. Sure a pencil works good on wood, but what about when I have to mark gray sheet metal? You need something that comes with different colors.