Which Yasawa island???

Hi all

Myself and my two best friends are travelling to fiji for a few weeks in july. We've decided on stopping over in beachcomber for a few nights, and spending a bit longer at oarsman's bay lodge, but are having trouble deciding between:

Octopus resort on Waya, (is this v similar to oarsmans?)
and...
Manta Ray Island resort

We're all 20 years old, and would love a somewhere where theres stacks to keep us busy (hiking, kayaking, snorkelling, nice bar...) but perhaps not too couply...

any ideas would be greatly appreciated!