Pros & Cons of Watir, Selenium or Sahi tools

Watir

Pros:

• It’s a Ruby library
• Multi browser (& OS) support
• Has a rich API
• Has a ‘Simple’ class (for non-tech users)
• Watij & Watin (Java & .NET)
• gives more stable and straightforward feeling
• automatically waits for the page to finish loading
• can detect when it's finished loading
• Watir's API more. It's richer than Selenium's
• provides an "attach" method which lets me programmatic access both
  the original domain window and the linked domain window from the same test.

Cons:

• Have to learn Ruby (unless you choose
  Watij or Watin)
• Every browser requires a different
  library

Selenium

Pros:

• Multi browser, OS & language support
• Install server-side or as FF add-on
• Has its own IDE, which speed up development
• Record and playback tests
• selenium rc + selenium ide (firefox plugin) for recording and playback of test case is great for generating test case on the fly
• Choice of programming language
• using JAVA through CruiseControl, make it easy to conver the selenium test code to JAVA

Cons:

• Have to learn a vendorscript => Selenese (Unless you write tests
  in another language which it supports. Then you just have to use the API
  reference which is straightforward.)
• has a lot of timing problems
• have to use the pause command (or Thread.sleep() if you use it in Java to wait for the loading to complete
• with Selenium is that it is very difficult to test complex multi-site apps
• clickAndWait is not helping when working with Ajax technology
• runs fine in firefox but had different problem on PC with IE6 and IE7
• learning curve is on the higher side
• IDE is nothing but a FireFox plugin...and it works only on FireFox
• record and play back only on FireFox and only if you install the plugin
• automation engineer needs to have reasonable experience on the chosen language
• need to implement most of the things including logging mechanisms
• Extensible Javascript APIs need a rebuild
• Selenium needed a lot of hand holding
• selenium doesn't support IE

Remarks:

• use clickAndWait to wait for the page to load
• using Java language
• Selenium 1.0 uses Javascript
• can use Python to run IE7 with Selenium Webdriver.

Sahi

Pros:

• Multi browser support
• Has its own IDE
• Record and playback tests
• Data-driven test via jdbc:odbc bridge (this allows to exploits data
  file as xls, mdb, csv, and .. every supportend jdbc:odbc driver)
• active community (fast replies to bugs/problem/suggestions)
• test success/failure reporting in html files
• capabilities to run test using batch file or ant script
• lightweight and not stress too much the host server.
• install once and use anywhere
• After Sahi server is running, tester can access Sahi Controller (aka IDE) from any supported browsers, no need for local installation
• including a script recorder, object inspector, log broser, debugger, utility to test code without recording
• Easy to learn, simple, powerful APIs
• Built-in color coded HTML logs
• Extensible Javascript APIs
• Extensible on the server with Java
• Parallel execution of tests
• Multiple domain scripting
• its not using x path
• supported IE

Cons:

• Confusing interface
• Least developed/smallest community
• documentation needs to be enhanced 
• need to be improved reporting
• needs more visibility on the web
• controller can be a bit quirky need some learning curve

Remarks:

• Javascript as the scripting language
• similar in concept to Selenium