[silon]

I found that Apache jmeter works well for me. Easier to use than Grinder, but much more useful than the MS tool.

[kowsik]

problem with most load testing tools is the fact that you have to script through them. It's a PITA. Especially with PaaS and Heroku/EngineYard/Other-Vendors/-style deployments, time-to-deploy often obsoletes the time-to-script-test-cases. Need something different, agile and continuous.