the more wattage, the greater bass response is in my experience. that bass response is attributed to the head room, so headroom is def. desirable. the valve king is really brittle sounding and won`t get the tightness you crave (ive tried it) i would not rule out the marshall. consider using a tubescreamer to increase the gain. i have gotten awesome, tight kse style tones out of a 60w jcm 900 with a tube screamer in the front end. i vote marshall!