There are several noticeable improvements and differences:

As to searching contacts...much faster.

When moving applications, little 'x' appears on non apple applications...you can still move them all but only non apple ones vibrate and have x

Maps seems to be "speedier" and gps seems to work better though not quicker.

Mail is still exhibiting delays which can be quite time consuming when switching between mail list and reading. If checking mail and trying to write, noticeable delay when typing in initial email address if it is comparing to contact list.

I would not hesitate to download update....There is still more work to be done.