Originally Posted by Unregistered

You may want to wait until the bond crystal system gets implemented, since you can never have too many of these and fusing golds/rainbows rewards a good number of them.

Otherwise, gold are usually better off being fused. Rainbows are the same, unless you're a hardcore min/maxer and want to hit 720k power when blooming comes out.

I have no idea what Crystal System or Blooming is xD