Well, my weight hasn't moved beyond the margin of error (unsurprising), but I'm thinking the pedometer was a good motivator. Yesterday, I clocked 12,879 steps, which for my programmed stride is about 7.5 miles. I burned a whopping 1026 kcal, if this thing's to be believed. That's a 6 pack of beer right there! ;-)
I was having trouble before with the walking, and I figured out what it was: I was just walking way too damn fast. On my initial day, I clocked about 110 steps/min and had a little burn but was fine. On those next couple days that my "legs gave out," I have no idea how fast I was walking. I thought I was going the same rate, but I wasn't. I decided to "slow it down a bit," and when I clocked the new, slow rate, I was going.... 110 steps/min.
Yesterday's long walk was closer to 100 steps/min, though, and my legs never even hinted at a burn. At 110 steps/min there'd be a slight burn after 10 minutes and I was ready to be done at 20. At 100 I was able to walk for 70 minutes straight. I guess it's like speeding vs. fuel economy. Fuel economy drops non-linearly as you go faster as your car works quadratically harder to go fast.