Opensource might actually be better.
In case you are in the process of evaluating test tools, this review by Forrester research might give you a good initial overview of the current commercial offerings - The Forrester Wave™: Functional Testing Solutions, Q3 2008
It looks at solutions that support the whole testing and quality management process and the conclusion is not surprising:
"In today's market, HP is the default choice"
I find the whole thing objective and if you read it carefully you will be able to find the key facts about the automation tools.
The evaluated vendors and the corresponding tools are HP (ex Mercury) with QuickTest Professional, IBM (ex Rational) with Rational Functional Tester, Compuware with TestPartner, Borland (ex Segue) with SilkTest plus also tools from Empirix and Seapine.
The review has its main emphasis on test management and not on test automation:
"Testing teams looking to purchase just a single product should focus on test management first, since mature practices in this area are a prerequisite for success with test automation."
While this sounds logical at first, I somehow can not agree with it entirely. But what follows is really interesting:
"There are exceptions, though: most notably, development teams looking to automate their own regression testing. Commercial test automation tools, however, tend to be less effective here than open source alternatives like FIT/FitNesse or Selenium."
and:
"Both open source testing tools and SOA testing tools are relatively small parts of the functional testing tools market, but they’re growing in importance. Why? Because iterative development methodologies demand that test automation start earlier in the life cycle, and the testing organizations that purchase commercial tools struggle to make this a reality."
It seems that the analysts that wrote this really have some insignt in the business. Overall it is a very interesting read. Did you know that the element Selenium is the antidote to Mercury poisoning?