Depending on what I am doing (and bear in mind my frequent disagreements with electricity!) i will cut the insulation with the pen blade, then switch to the stripper notch to pull it off. Last week I installed a new stereo in my car using that method. I had to splice a wiring harness to the stereo and I think there were about 20 wires all told, so I cut them all then stripped them all. Took no time to do and worked like a charm.
Of course, if you are only doing one or two wires then switching back and forth would probably be a pain.
Def