Or do you mean using HD diskettes in a DD drive? This can result in very unreliable disks. The data will be fine on the short term but over longer periods of time you have the chance the data will degrade very rapidly.
I mostly only used HD floppies for my amiga and i have ones that were made over 10-15 years ago and most of them worked perfectly when i tested them a few months ago.
One thing i have noticed though, is that my newer floppies is VERY unreliable as i cannot even format more than 20% of them now.
Anyhow, most of floppies were in perfectly good condition, as were the data on them. The ones that didn't work properly I formated, again and again, until they seemed fine (didn't give strange noises when read and/or stalling the application used when formating them).
Why is that? I have noticed this too with problematic floppies, that it helps to retry format until it is succesfull. Once it is is succesfull, it seems to work perfect without errors. This again is something i have noticed mostly with newer floppies.
