there's no 'better' here- it's what you like after hearing both in action.
the MG15MSII is better off in its drive mode. add a mild drive booster to it & the saturation would shame some mid-priced amps out there. if you rely on a default amp's drive, this one is recommended.
the Frontman amps (those i've tried), has this signature Fender cleans; it's not tube driven but you know it's Fender when you hear it. driven, i find that majority of the small Fender combos, this one included, eminating too much top end hiss; you'll enjoy hooking up pedals to the clean channel rather than rely on the default dirt here.