I think you need to take a look at the improved version of SOASTA Concerto. The latest version offers Web UI/Ajax testing support so that Ajax based web applications match the standards of Web 2.0 businesses and this release is being regarded as one of the most powerful cross browser Web UI/Ajax testing solution available as of now in the market.

Given below are some of the major features of SOASTA Concerto's Web UI/Ajax capability:

Automated Browser Recording: SOASTA Concerto's automated browser recording captures all of the user's browser actions (i.e. click, type, mouse down, mouse up, mouse over, select, drag, drop, submit, etc.) and automatically adds each action to the test that is being created. This allows for fast and easy creation of the basics of a Web UI/Ajax test.

Cross-browser Support: SOASTA Concerto supports automated Web UI/Ajax testing for Internet Explorer (IE), Firefox, and Safari.

Monitoring: SOASTA Concerto monitors all three tiers of a Web application - from the Web service, to the Web server, to the browser. In addition, SOASTA Concerto monitors network devices (i.e. routers, firewalls, and load balancers), as well as software resources (i.e. application servers and databases) that are part of the Web application infrastructure.

Integrated Analytics: SOASTA Concerto supplies users with instantly available, pre-built analytics to document all test results. Users can immediately drill through charts all the way down to the exact message or event to understand, diagnose, and analyze test results.

Scalable, Distributed Architecture: A scalable, distributed architecture allows users to build a test that simultaneously runs multiple browsers distributed in the testing lab or around the world for one unified test result.

Do let me know what you think about it.