- Saxon is great for off-line testing (primarily while developing small bits of code or trying new programming techniques). It cannot fetch the information from the server, so you have to provide test data in local XML files
- Firefox is the best tool if you want to test client-server integration and use <?xsl-stylesheet ?> approach as it can recover from XSLT errors (which IE can't). However, it doesn't detect all errors, so the stylesheets working with Firefox might break in IE (but not due to an IE bug)
- IE is a nightmare when using <?xsl-stylesheet ?> directive. Whenever something breaks (error in stylesheet or even server-side error resulting in HTML response instead of XML response), its cache gets messed up and you have to restart the browser to continue the tests. I therefore use IE only in the final tests to verify that my XSLT has no weird errors not detected by Firefox.