I used to have a Reslo ribbon mike years ago. You are right about them being warm. It is due to the fact that the lowers frequencies get excessive amplification because the wave crests are further apart and the wave pushes the front of the ribbon while the previous wave is pulling from the back.

You will also notice that a Dynamic mic is warmer than a condenser. But that is due more to the fact that it doesn't amplify the high frequencies so well. So if you have a squeaky voice you might want to go with the dynamic.

You could of course try them out and poll your audience.