I switched from Norton (5 licenses) to MSE for a couple of reasons.
First, Norton was slowing down the system and consuming huge amounts of memory. Not so much a problem on Win7 but on my older XP systems with limited CPU and RAM it's a killer.
Second, Norton charged my credit card for a subscription update without me initiating the transaction. They called it "enhanced customer service", I called it "you just lost a customer". Used to be when a subscription ran out they nagged repeatedly and pushed you to their website where you had to acknowledge that you wanted to buy another year's sub. Now the default is "we charge you automatically". You can opt out - if you know about it.
These days I use Ubuntu about 90% of the time but for the 10% that's spent on Windows 7 MSE seems to be working (no hits yet so hard to verify that) and the resource use is much less intrusive (so far). I still have Norton on one system (the one I paid for automatically) but when that runs out - I'd done with Norton.
I've used some other AVs, best left un-named, but their sig update process was so unstable I had to ditch them.
Judging by: http://www.av-comparatives.org/images/stories/test/ondret/avc_od_aug2010.pdf they seem to have slipped a bit over the past 9 months. (Which is a shame as I use it too)
– Joe Taylor – 2010-11-29T13:32:38.790Bear in mind that security is an extremely difficult thing for the non professional to judge, so I'd consider the second question more valuable. – David Thornley – 2009-09-29T16:52:57.433
@alex, It was meant as a joke :\ – Phoshi – 2009-09-29T17:14:25.203
@Phoshi sorry, I didn't mean to sound that harsh. I should relax a bit :) – alex – 2009-09-29T20:33:56.143
I don't think anything can beat Kaspersky Internet Security. It's virus base is the widest (~10M viruses) and Avast+MSE+etc base can't rich him. Maybe Symantec Internet Security can reach, but I don't think so – Searush – 2012-11-05T19:37:38.177