<p>For features comparison of Web Canoo Web Functional Test  and Selenium software, it would be good have an assessment, in terms of integration to Java platform applications, speed, how quick is it to deploy Tests, execute, and analyze results, JavaScript support etc. 
I am using Canoo project, it is pretty good. </p>

<p>Tatyana</p>

So I initially pursued Canoo as a direction for functional tests.
I ended up choosing Selenium as we saw that running selenium in browser
was a better fit for us than Canoo which uses HTTPUnit to run tests.
If you are running tests at build time with selenium you will need to
have the browser
software you wish to use on the build server.  It is not possible for
us to test IE on our build
server for example....So we only run the tests in Firefox.
The killer feature for us was the Selenium IDE.   We have folks using
the selenium IDE
who are not  really developers which is a great help.   The development team
works with them to make sure the tests are running properly.
Canoo has its own advantages that,  A rather biased blog entry is here:
http://mguillem.wordpress.com/2007/10/29/webtest-vs-selenium-webtest-wins-13-5/
Note that in spite of all those things I still prefer Selenium...