If you haven't checked out the website for Pythian, it's well worth your time.. Here is an example of a post on exadata and flash cache.
http://www.pythian.com/news/18077/exada ... up+Blog%29
The main blogger is Alex Gorbachev, and he also posts quite a bit to the linked exadata group (well worth joining). He has great insite, and his company has a lot of useful information.