I found it to be quite good, although I now use a 50mm Apo-Rodagon, which is really excellent. Although it may well have field curvature, I reckon that stopped down a couple would see it off.
I must admit that 40mm on the V35 is great if you are printing a bit larger, also ties in with the autofocus. I think that Schneider makes a 40mm Apo-Componon...probably very expensive!