Re: What are the major differences between WR 6.0 and 5.0?
The attached text file, unless otherwise noted, was taken directly from the online help's "What's New in WinRunner 6.02" section. WinRunner 6.02 is the latest release of version 6.0.
I believe that if you are involved in testing Web applications you should consider moving up to this release, as signficant enhancements have been added in that area[and the Webtest add-in is now integrated with version 6.x].
As to your question about stability I can't compare it with version 5.0 [not having used that release] but I find this version to be reasonably stable [of course with a product this complex there are bugs and annoyances].