Reply to Speakers: Watts Vs. Size

Hey,

Currently choosing between:


BEHRINGER B812NEO
BEHRINGER B215D

But what is more important in a Loudspeaker? The Wattage or the Size?

P.S
If it'd help either would be paired with a BEHRINGER B1500D Sub.

Not looking for which is better.

Please justify you answer with a short statement saying why the answer you have chosen is better.

P.S.S
As you may be able to tell i'm looking in the Behringer line. Any other speaker suggestions shall be appreciated.