So, I tried AG and found that in a quick test, I could probably run twice the number of Etherium instances before Pro Tools gives up. Pro Tools meters go into red at around 23 instances. However, I tried Genesis on just one track before, in a mastering situation, and it seems that if you run more than two or three instances on the same track in pro tools, it goes bananas, but I can run well over 20 of them as long as they are spread out over different tracks. Audio Gridder helps a lot with the problem of running several heavy plugins on the same track (often the master bus). I had Activity Monitor running to see how much the cpu really was working. The meter in Pro Tools is not always telling the truth... On the actual true CPU meter, there actually is no difference in how much cpu is being used, but PT caves in well before the actual CPU limit is reached. In fact, running just one instance taxes the CPU more through audio gridder, which makes sense, since AG needs some juice to run. But as an example, just one instance of Genesis Etherium registers almost 30 percent of Pro Tools Cpu, whereas it only is 1-2 percent of the actual computer CPU. In pro tools, a lot of plugins use insane amounts of cpu, and most dont move the bars at all. So, it has got to do with the AAX coding. Acoustica are among the worst in that regard and Pulsar Modular are pretty heavy in Pro Tools as well, as is Oeksound Bloom to name a few. Ozone is heavy as well, but it runs a lot of processes...
So, in short AG lets me use more instances of heavy plugins in Pro Tools and helps out the most on the master bus for chaining the really good and heavy plugins.