I have both the Fisher X-101-C and the Sherwood S5500-II. I haven't restored the Sherwood yet though so I can't do a fair sonic comparison but I can compare other things.
Physical ratings:
Mechanical design - both are cool. Sherwood and Fisher are both mid-century modern masterpieces. Sherwood is vertically smaller and the design layout with the copper chassis and angled caps and tubes is compelling. Points to Sherwood
Cabinetry - Sherwood has a metal cabinet and Fisher uses a standard Fisher integrated sized cabinet. Points to Fisher.
Controls - Sherwood has somewhat incomprehensible speaker wiring, very tight RCA inputs and an odd but well loved set of rotary controls on the front cover. Fisher has a couple knobs, some pushbuttons and a hideaway front panel for most knobs and all switches. Points to Fisher.
Working space under the chassis - Can't do a fair comparison.
My S5500-II uses 7868 outputs, not 7591s as the Fisher does.
Audio ratings:
Sonics - I can't do a fair rating because the Fisher is totally restored and the Sherwood is totally unrestored.
I can say that the Fisher X-101-C is my favorite of all Fishers that i've heard so far and I've heard at least eight models. That sets a high level for the Sherwood to meet but rumor has it that the Sherwood is up to the challenge when restored.
Hope this helps.