I'll use Webroot's SpySweeper as an example. The release upto v5.0 was very good and on the money. Then V5.5 came out and it got bloated and seemed to slow down alot or the system. They did provide a patch to help correct or provide info to help resolve. Now, that wouldn't be so readily done with freeware/shareware unless of course it was doing harm and users got "real angry" or the fix response would be slow.
Now, you can point to paid for version like MS OneCare as real lackluster but Giant that originally owned it was pretty darn good before MS brought it. MS, is all that needs to be said.
As for Symantec AV, it was good upto 2003 and then I ran away after all the problems. But at least they tried to fix some problems, try with freeware, etc. and it just doesn't happen at least on a timely basis. Yeah, I know about McAfee too, but it does do the job when truly up and running. It seems some users are pissed when they can't get rid of it.
I use small freeware pgms. that do one job/task very well, but hardly progresses from there. Usually, that task/job is rolled into paid versions or commercials as just more item to do, which can start the bloated process.
I just don't want too many users singing the virtues of freeware/shareware simply because its free or low cost and just on that be too comfortable. Commercial releases do a darn good job of trying to provide a decent product and have quick fixes/cures/updates on a daily or hourly basis, that just isn't readily so with the others. I use ZoneAlarm Free, but find the updates really painful due their ever increasing size, heck I use dial-up but that's me. So getting the paid for version wouldn't cure that issue but still I like ZoneAlarm(free). There is a seesaw pattern of what's good and bad, I just wanted to point out some weakness in freeware/shareware that when tested(magazines&websites) seem to have lower scores on many of the attacks out there. But, at least they do stop many/some blatant malware.