I like the paper book and asked for one but next year for the first time in 2010 the electronic version is the official rule book. SCCA members are now 90% online. National expects some savings from printing fewer books. I would also think that the printed version might not be out quite as fast as previous years.
It will certainly take some getting used to. Not so sure about having to look something up on a cold rainy day while teching a car.