Mer-say-teas is how I pronounce my name. People like to tease me on how I'm a car, they think it's funny but it really hurts my feelings. Mercedes is a great name, I don't think it matches me, but there's really no other name I would like to have.
This is my grandmother's middle name and she has always pronounced it as "mer-suh-DEEZ." I don't know where her pronunciation came from but I've always liked it, even if it isn't correct.