Forum Friday: Do you write in sprints or marathons?

What I mean by that is, Do you power-write in quick bursts (say, 300-500 words in an hour) or are you more likely to stake a place in a café or library for the day and work at a slower but steadier pace?

I think this is an especially relevant topic as the ~1,700 word-a-day madness that is Nanowrimo approaches. Tell us what works best for you!