I finally snagged a copy of SuperFreakonomics from the library a number of days ago and recently completed it. I posted earlier on its cute little gibes at macroeconomists, which remind me a lot of how sociologists tease economists in general. My overall impression is that like its predecessor, it's a really fun read.
Fun often includes several other emotions too, of course. Riding a roller coaster, you're likely to feel fear, g-forces, nausea, elation, and disappointment when the ride ends. The book lost me early on with its rather snarky writing style, which I felt like it either lost or I became more accustomed to as I read further. I think Levitt and Dubner are providing a public service in revealing the "hidden side of everything," but too often they overplay the amorality and smarty-pants cards. I would agree that those are more appropriate in a popular book than in academic discourse, however.
The back-and-forth over the global warming chapter to me is just humorous. The geo-engineering efforts of the I.V. to me feel recycled from a New Yorker article on the same topic from 2008. I have no problem with their reemphasizing those ideas to a wider(?) audience. Meanwhile, Brad DeLong and Paul Krugman seem to, or perhaps they're misinterpreting the direction of the chapter as hostile denial.
To me, the best aspect of SuperFreakonomics is that it provides a well-written and accessible summary of a lot of economic research that to ordinary people is likely to sound like it matters. And it's not about unemployment, stock prices, or interest rates. I wholeheartedly recommend this book to anyone interested in a round-up of clever ways to think about the world.