I just got off the phone with a rep from 125west.com. Here are the differences between the Atlantis and Apollo lines:
Atlantis: polished finish (shows fingerprints), lined with copper to the rim (even on their sauteuses), cast handles
Apollo: brushed finish (hides fingerprints), lined with aluminum
The lids are identical (apart from the handles), so one could buy Apollo lids for Atlantis pans. The pyrex lids fit just as securely as their stainless counterparts.
Both the 125 and Sur la Table reps I spoke with use Apollo, as it's slightly less expensive, a "great value for the money", and both also claim that it's more cookware than anyone will ever need. 125 is also offering a special discount if you phone your order in.