I've only done it one other year (two years ago...I think...) and I nailed it.
Nearly every other year I've been in the thick of another project, and didn't want to put on the breaks to crank out something "new".
But I'm about to finish my current WIP, like probably tomorrow, and I want something new ready to jump into right away.
Something about autumn turns me into a writing machine. That coupled with the fact that this is the part of the year in which time starts to suddenly move faster, and commitments pile up like snow until you are buried in parties and activities and gatherings - all of which are fun, but it is an easy time to lose track of yourself.
So what I'm saying is, I'm leaning towards taking a crack at NaNo this year.