Honestly, the thing installed in under a minute, without the need for a restart! The computer did not slow down whatsoever, and it just looked slick! That said, I did go back to Avast only because there was not enough feedback on its engine, and mere speed/aesthetic improvements will not suck me back into the Norton universe. I was shocked by just how many of the typical Norton issues have actually been fixed by Symantec.
I must say one thing about ijack's comment about Norton - I really did give norton a fair chance a few years back, but when I removed it and installed Avast in its place, a whole bunch of stuff were detected by Avast's boot-up scan, so I decided never to trust Norton or invest into any of their products - but given my work, I got a few free cd keys for Norton Internet Security 2009, but before I activated any, I installed the trial version.