Well to begin with, start by searching the other topics on here as there have been many discussions on the differences/best tool etc.
In short....there is NO best tool but only a best tool for the software your testing.
Consider these for a start.....
Q) What programming/development environments is your software developed in?
A) Not all test tools will support all environments or at least some support them better than others. If your looking at only Web testing, there are a number of dedicated Web only testing tools out there which may be a better bet.
Q) Do you make much use of custom controls in your software?
A) Some tools are bad at working with custom controls and most have difficulties with identifying them correctly.
..and the list of Q and A goes on.....
Take a look at Elfriede Dustins book on Automated Testing. There is a section dedicated to Tool evaluation and a Test Tool evaluation matrix that can be used to value each tool by its merits.
Its worth taking time to evaluate especially with Performance tools(expensive).
However, there is no real answer to this type of Tool V Tool question.
Where did you come to ask yourself which is best between Silk and Mercury? These are just 2 Test-Tool companies. There are many more out there selling Test-Tools.
if it works, leave it well alone....if it does not work......ship it!
Can someone highlight the differences (preference over the other) between Win Runner and Silk ?
I would greatly appreciate if someone can compare the two for web-based/client-server applns and in some other areas like performance/load testing and clearly
justify as why Win Runner is superior or a better option than Silk or vice-versa.
Alternately, if I were to select a tool for
automation, what are the key areas that need to be identified before I can come up with a solution.