Serious question: as a user (not as a developer!), have you ever seen substantial improvement in a piece of a software from a ground-up rewrite?

In other words, have you ever used (but not co-developed) something where the developer(s) decided on stopping evolutionary work and instead embarked on a substantial rewrite, and the outcome as you saw it firsthand was a real improvement?

If so, please state your example. Please stick to personal experience, rather than hearsay. Thanks!

@xahteiwi
Well, since people seem oblivious: Netscape 6 (and its continuation, Mozilla) was infinitely better than Netscape 4, when it was finally out. Of note, a rewrite of probably comparable magnitude - the breaking of the Suite to produce Firefox (yeah, some names nobody remembers in the middle) - did not give immediate returns, but I do believe it contributed to the project's longevity.