For Floating Ruins, there are two primary differences.
The first is that, in the PS3 version, you'll want to gather the Elixir Base relic. The only other way is to get it via DLC.
The second is that you may want to find the Tracker monster, as it's missable. Aside from that, there's nothing in the Floating version that can't be found in the Fallen version.
Grade Values from Relic Farming: 50-99
Sky King Fossil is very rare. And you need it for Awin's best weapon, unfortunately.
The first breakable honeycomb is here. Breaking all four will unlock the hardest form of the final boss. Even if you break all four, you can reverse your decision later if the boss whoops you. You only need to break one for the trophy.
The next two honeycombs are here.
The final honeycomb is here.
Technically speaking, Flameu has five separate encyclopedia entries, depending on how many honeycombs you broke. This determines her level.