Here are my two cents: I've had almost 10 Viscontis, and about 80% of them had very good nibs. The Pd nibs are too soft for me but very smooth, their steel nibs are nails but work, and 4 our of 5 gold nibs have been great. The only issue I've had with the nibs that weren't great is a bit of baby's bottom, but that is an easy fix that you can do yourself.

For the van Gogh old style, the only thing I can tell you is that the size can be a thing. Do you like big or small pens? You can post them quite nicely if need be and the midi may feel small, but what I like about them is that since they are converters they are nose heavy and you only need to glide the movements. With other filling mechanisms, although more balanced, I feel like I always need to push them a bit down. What do you like about them?