About 35 years a go I bought a Legend Mine is rubber coated and still works good up to about 40 power it never did focus well enough over that to suit me.
O n the other hand I bought a new Leopold SX-1 Ventana 20x60 X 80mm and it works clear a bell on all powers, is easy to focus and I am thrilled with it.
I believe that the 80 mm lens makes a big difference on high powers.