Definatly flowing water, if you don't have flowing water you also won't have anything to keep your beneficial bacteria alive in your filter with so a constantly running filter is a must as well.
I would go for slow. But I guess they hang about the bottom and don't feel the strong current as much in my tank. THey like to sit still so I would think they like slow. But I have a strong cureent at the top for the danios
For the corys, try for a happy medium. While they like swimming in the water flowing from the filter, and will often spawn under it, if it is too strong, they will spend a lot of their time in their cave trying to get some rest.