Houston (as of Jan 2008) was about 15 drop off and 5 to pick up. I haven't applied since then but it seemed very efficient, and I just went on mid-mornings that were convenient since it was near my neighborhoods.
The trick we used successful for a multi 1 yr tourist was to put down we'd be in China longer than X, which was somewhere around a week (I did end up entering 3 times, for 1 day, 1 week, and 2 weeks).