What's your NP budget?
And yes, a RCG will do more damage than a good Muffin, but only marginally. ~1-2 more icons, averaged.
Muffins are cheap as dirt now, you'd only want a RCG if you already have it, or are too lazy to keep re-equipping Muffins between battles.
I say skip the RCG and stick with Muffins until you can get a G-Bomb. Use that RCG money on 2x 13-icon constants instead, like YBlaster, Brynns Sword, and ACTS.