I've read that 50's German Oblique nibs were ground different; made to shade.
I have been lucky and have couple. I have an OB, a KOB and a OF, all are semi flex, all 14 K*, all are a joy to write with. These nibs dance. They were designed to produce shading.
I have a 18 K OB Lamy Persona....a nail, made for folks that hold their pens crooked. That nib has to go...a 14 K old ground style semi-flex or an OM...in that I don't have that would be great.
I don't have any more modern Obliques...and have no intention of ever buying one....
* In this case I don't think a 14 K gold nib must be better than a very good steel nib, I have a Osimia Supera nib normal M, that is semi-flex.
What is your experence with Oblique nibs, modern or 60's/50's and earlier?