If you are using a "low/network" level tool like htmlunit then it

has the advantage of being fast - but its javascript will

not work work in most complex websites(besides not being a browser test)

Selenium(java, .net) code also has the disadvantage of being dependent on RC server(not big deal).

You should continue low level tools like httpunit etc to use

it for monitoring - but don't use those tools for browser/regression testing.