I have been a fan of Mathematica ever since high school and used it throughout my university years and even to date, I continue to use it. Mathematica is a well received application or a computational platform as many refer to it as.
There is some thing new from the Wolfram Research, the company that gave us the Mamthematica, a Web-based "computation engine"--Wolfram Alpha-- Alpha accesses databases that are maintained by Wolfram Research, or licensed from others, and deploys formulas and algorithms to compute answers for searchers.
When I read the test done by Technology Review, I had to smile, typical mathematica, to the point.
I know O will have a permanent bookmark to Wolfram Alpha.
You can read Technology Review article to get detailed information on Google and WolframAlpha comparison.