Solid state amp for Primaluna Prologue Premium Preamp

I recently upgraded my Preamp to a PrimaLuna Prologue Premium Preamp. I am enjoying the improvement it is making in my set up. I left my power amp, a Rotel RB991 driving Magnepan MG 12QRs in place. I am contemplating replacing it with a PS Audio Stellar S300 since a pair of PS Audio Stellar M700 are not in the budget with two kids in college. Would the Stellar S300 be good upgrade path? Any other suggestions new or used?