What is a good electronic distributor for an rb/b block?

Summit Billet distributor is a good piece, I have the SBM version on both of my Mopars (Duster and D200, both with 360s). Mag pickup inside just like the factory Mopar electronic ones and a similar style of mechanical advance system but IMO easier to adjust and comes with an assortment of advance springs and plastic "keys" for setting the mechanical advance limit.

Here's the version for an RB engine: DODGE Summit Racing SUM-851008 Summit Racing™ Billet Electronic Mopar Distributors | Summit Racing