Of course "best" is a matter of preference; "favorite" might be a better word. I've owned three that really rocked my world: 1: Marshall Valvestate. 12AX7 preamp, solid state power amp. Not exactly a JCM800 in tone, but had a real tight bottom end that was great for metal. 2: Marshall Artist 3203 head. Reverse of the Valvestate; solid state preamp, EL84 power section (if I remember right). This amp had a dark, nasty 100% Marshall tone. 3: Dean Markley RM-40-SR rackmount. I don't know why I ever got rid of this. 12AX7 preamp, solid state power amp. Rich, creamy, vintagey overdrive. The beautiful fat tone from this can only be described with stupid words such as those. This photo is not of mine, but it's the same model.