On the downside, it is easy to miss a key or skip a letter if I don't type carefully. But I'm finding this improves with practice, so even though it will take some getting used to, I think I might keep it.
UPDATE: I have gone ahead and preordered a different keyboard: the Jorno. It is not available yet, and it's supposed to ship March 31st. I think it'll be more durable for traveling, and it is probably closer to a full-size keyboard, but it weighs just over 8 ounces and has the built-in Lithium Ion battery I wanted.