I have a 1946 J3C65 with a Lycoming 0235 C1, and it flies well. It does have 36 gallons in the wings, no nose tank, Supercub tail feathers, Supercub gear, Aft baggage cut out with cross tube like Supercub, Metal spars, and Supercub wing struts. It weighs #800 on wheels. No interior, no electrical system. All mods legal by STC or Field Approval.. maybe not possible now.
I bought it as a basket case when I was 15 so really had no choice... All I was hoping for was a Taylorcraft or Champ... felt pretty lucky to get any Cub! ($2200 with skis in 1976)
As to buying one now, I would say the wing tanks, metal spar, and big tailfeathers would be something I wouldn't want to leave out.
The things I missed when I flew it a lot were the lack of flaps, and I didn't like the spar in my face.
The flap part only mattered to me when landing on slippery short strips because it was hard to land slow enough and still see where I was going. The spar in the middle - well, the cotter pin on the aileron cable kept catching my hair - back when I had some there.. I always flew it from the front and control-authority always felt fine.
So I've always kind of thought an early PA 18 would be nice, to have basically the same airplane but with flaps and spar in the wing roots.
My Cub would perform right with a 150HP stock Supercub until any weight was put in it. From what I've observed, nothing beats a real Supercub for utility.
But I would say if the one you're looking at is the one that is within your reach, don't be afraid of it's flying qualities. It is a bit of a hot rod.