I still have a BYOA account with AOL because it's the E-mail address I've had since I first had one and I use it for shopping now... so all the spam goes there instead of my insightbb account.
Let me clear up some myths:
I have never had the AOL client freeze up my system.
In the last two years, AOL has done an AMAZING job cleaning up spam and adding customizable filters. I get a tiny fraction of the spam I used to get on my account. Maybe 1-3 a day.
AOL is far less likely to spread viruses for newbies, unlike outlook express. All the self propagating email viruses do not work with AOL. If they get a virus, it stops with them unless they forward it intentionally.
All the "default" stuff is EASILY stopped. In fact, AOL will NOT become your default E-mail or browser unless you click "yes" to a VERY clear and specific prompt. And even then, if you do click yes, it is easily reversed.
The E-mail is extremely easy to use. This is why, when dealing with computer illiterate idiots like my GF's mother, I have them use AOL. The damn thing is fool proof.
I have never been told any of my preferences were set to expire, including the preference that turns off popup ads within AOL's client.
Finally, I have never had trouble installing, or uninstalling multiple versions of AOL. Though, I've never had more than two incremental versions on a system at one time. Why would you have any more?
Is AOL great? No. It's made for newbies and idiots. But it's not the devil so many make it out to be. If your folks are comfortable with it, leave them be.