The chromed bronze Record derailleur, although closely resembling the Gran Sport it replaced, is vastly superior. It has a limited range (about the same as NR), but is smooth, precise, tough and never wears out. The plastic pulleys crack & wear: that's about it. The Record felt great from day one, not needing to break in the way the NR did.
It is also very beautiful.
If you are using a close ratio 5speed cluster, say 14-22, & 42/52 chainrings, you can't find a better derailleur, IM(not so)HO.