I just had to check to see if a mouse would work on the PS3 and was ecstatic to see that it does.
With a keyboard, mouse and controller all available for inputting commands, activities such as battle, item management, equipping armor are easier than I have ever seen before.
Drag-and-Drop: Thank you! The drag-and-drop UI options for equipping items is an incredible improvement. You can even use drag-and-drop from the Ability menu to assign abilities to your controller hotbar. Great to see the Mouse and Controller actually working together.
The ability to just press X on the controller to interact with items on the ground is a big plus. (Remember when you had to go into the menu to open a chest? Bah, glad that's over.) The auto-targeting of things directly in front of you seems pretty intuitive so far.
And as for targeting, d-pad is UP/DOWN for party members and LEFT/RIGHT for mobs. Woohoo! They really did listen and implement the feedback.
I do hope that the ability to re-map controller functions will be included at some point in the future (Looking at you, R3 = first-person camera. I DON'T want to accidentally 1st person during combat, thank you.)
One problem I did have with all three components hooked up: When I went into the menu via controller, all was good. But when I opened the menu via the keyboard shortcut, I could not figure out what keys moved the cursor around the menu. Left/right/up/down/strafe-right/strafe-left would all move my character, not the menu cursor. Anyone know the answer to this?
Anyway, I had some friends that were not aware that the PS3 would support a mouse, so I wanted to make sure to recommend it to all of those playing on PS3!