I can destroy a tune with t-racks and ozone, yet I haven't been able to inflict any serious damage to a song using AAMS. I've got to admit that it can do a pretty good job, and considering it is free, there is no reason not to give it a try (windows only?).
 
(Of course anything to be sold/distributed should go through an ME)

You can destroy any track with any plugin if it's used too heavy-handedly.
 
And you shouldn't be using anything like those sort of settings in a mastering context.
 
Mastering is, or should, be just adding the final sprinkle of fairy dust and loudening (within reason)
The historic application of mastering included making sure all songs on an album are of a complementary tone & volume, and getting it all prepared for vinyl cutting.
 

Mastering is like frosting on a cake....
If it is a "good" cake then the frosting gives it that final panache, coating and makes the taste buds tingle...
If it is a "not so good" cake then it is that sugary start to reaching for a napkin and moving quickly but politely to the rest room....

I usually master right inside the project, unless I'm specifically mastering for an album, in which case I load all the tracks into a separate project. When I master inside the project it helps me to notice things in the mix that I need to change, so I like having everything integrated.
 
My main mix FX chain is usually this: Mastering EQ -> Cakewalk TubeLeveler -> Limiter No6. I HIGHLY RECOMMEND LIMITER NO6. It's a free 64-bit VST mastering compressor/limiter plugin that sounds awesome. Since I started using it my songs have started sounding way better. (I use the compressor, peak limiter, and protection sections and ignore the other stuff in the middle.)

Smurf43
I use the AAMS mastering system, there is none better out there, besides paying for someone to do it.....

Newbie question what is AAMS?

AAMS website

Are any of you using Waves plugins for that commercial polish during Mastering or any 3rd party Mastering effects for that matter?
 

I use my T-Racks plugs.
 
There's not a lot of ground they don't cover between them, and I still think their Brickwall Limiter is one of the best out there.

I'd bounce your stuff down to a 24 bit stereo wave file once the mixing is complete. Then master on that. These 7 "Mastering Revealed" videos on youtube are quite an eye opener on mastering. Start here at #1
http://www.youtube.com/watch?v=dzSuvZXiccQ
 
 
 

I typically do my own Mastering (and please, no lectures on why I shouldn't ~ I'm also a Junior Mastering Engineer; I know why). What I typically do, since I'm aware of the tools and methods I'll often use in Mastering later, is add one or two of the plug-in models to my Master buss in Sonar. I will tweak those in a "nominal" fashion, to emulate how the final Master might translate through my Mains (speakers). If something's not working, I disable them and go back to the mix. This really saves time before sending a mix to another Mastering engineer, when I choose to. My own feedback loop saves money, too.
 
With that said, I recommend only doing this above when mixing. When you feel your mix is ready, disable those Mastering plugs and export the Entire Mix. Either re-import them into a new stereo track project strictly for Mastering, use another program designed for Mastering, or send the tracks off to the engineer from there. No changing bit-rates, please, unless you're Mastering for yourself!