Ryan, yes the Mehta performance is the one that I usually suggest and is probably my favorite of the six versions that I have. As to the "AMSI" processing, the Berliner lab which does it says that it's proprietary and doesn't describe precisely what they do, but it in someway involves having more than the usual amount of ambience in the mix. All CDs have ambience in some degree mixed into the two channels, which processing such as DPLII and Logic 7 can extract and steer to the surrounds where it belongs. Whatever the exact process, it certainly sounds good on the Planets CD, especially with DPLII.
Some of the Eloquence CDs are very good, and of course I don't know which ones that the store has, but looking at the link you gave to their catalog, some that I have or at least am familiar with are(catalog numbers you can insert into the search bar): 4674102(Gershwin); 4696282(Ravel);4674192(Rachmaninoff); 4674532(Rachmaninoff); 4674292(Mahler); 4674612(Strauss); 4697602(Dvorak); 4674632(Dvorak).
