I have a couple replies for the AIM+ features....
"Automatic (but optional) logging of all your IMs (even chat rooms!), creating a history which you can browse using the AIM+ History Viewer (part of AIM+)."
Logging is built into the Mac version of AIM.
"Ad-Removal - say goodbye to all those pesky ads that clutter up your Buddy List!"
There's a hack for the Mac version of AIM at
http://www.bluebomber.com/aimx/
This procedure removes the ads.
"Cloning - you can run multiple instances of AIM to sign on with as many different screennames as you want!"
True, can't run multiple screen names in the same AIM program, but if you use the official Mac AIM client, iChat, and Adium, that's three screen names you can run at the same time, right there.
"Adjust the transparency of your Buddy List or IM/Chat windows!"
If you love transparent windows, I suggest you look at WindowShade for OS X. it has all sorts of window-manipulation features.
http://www.unsanity.com/haxies/wsx/
Sorry we don't have something EXACTLY like that for Mac, but I think these things will help.