From my experience, appearance is the main selling point when customers consider finishes. They may like to hear that they picked a Titanium, Rhodium, or platinum pen, but it does not drive the sale.
I have also noticed that most customers have not heard of rhodium as a finish and I tell them that it is like platinum as far as color and durability.
In all honesty, I've put a chrome and a rhodium of the same kit side by side and was hard pressed to tell any difference. I haven't done platinum so I can't compare that to anything. My customers to date haven't had a preference or even understood the difference beyond what I tell them.
The difference is supposedly in the wear, but only time will tell :biggrin: