Well... after reading this thread and looking around at other forums, etc., I started playing with Ozone.
My first impression, using the "General" preset, was "This seems like it sounds good, but there are certain aspects of it that mangle the song." I plugged several different songs through the preset, and had the same impression with all of them, although it was usually something different that I didn't like, depending on the song.
Well, I sat down and read the entire 56 page user/mastering guide, going through the plug-in and the process step-by-step.
Two things happened: I felt like I got a much better understanding of "mastering" (put in quotes so as not to offend the "send it away and pay $$$ or it's not real mastering" crowd

), and I also came away feeling pretty impressed with Ozone.
I've "mastered" all of my songs, but always with a "press this button and see" approach. I've been happy with them, but I honestly feel like the song I just remastered using Ozone is better than I could have been capable of before. A lot of my previous mastering approach has been a hands-off affair; a little compression and maybe a touch of EQ, but that's it, if that.
I will have to play around more with Waves, but I do have to say that the Ozone interface is VERY appealing, and I could see that being the major factor, if the quality is similar, which to my (somewhat hyped and excited) ear, they are. Time will tell, I think, but right now I am pretty happy with the way Ozone worked for me. (I hope it's not just me being over-excited about a new toy, which I am totally abusing. lol)