There is obviously integration risk, but I believe the integration risk is low compared with the potential upside.
The reality of our world now is that almost everyone in every country living above poverty will own a smart phone.
Buying Motorola gives GOOG the ability to capitalize in a different way than just search and whatever value they get from the patent acquisition is bonus.
5 years from now, this will be viewed as an intelligent acquisition which provided a lot of value to GOOG, but most likely not the way most people are looking at it today.
*Scott's micro-basis is not a good way to look at this acquisition and by not looking at the big picture (mobile growth) he may have made a serious error.