A few years ago he was on the "Adam and Joe Go Tokyo" show. Here is a clip of him talking about his inventions. http://www.youtube.com/watch?v=NjuyqjXbHKw

The ASTER data is at a much higher resolution, but it is debatable if it is much better accuracy than SRTM. I think even the wikipedia page mentions this. I think the problem is the two data sources are developed using very different methods (InSAR vs photometric stereo). The error in SRTM is quite obvious, large voids and no signal areas. ASTER suffers from high frequency noise and poor feature matching in complex scenes, these types of errors are not so easy to detect and account for.

The raw data, as well as data from multiple other sources can be downloaded from NASA's Earth Explorer http://edcsns17.cr.usgs.gov/EarthExplorer/. The article doesn't really address the fact that the Google data has been cleaned up a lot. SRTM has a lot of voids and areas of poor quality, especially over mountains. The resolution of the data is worse for anywhere outside of the USA.