When my daughter was diagnosed, the doctor said CRPS was the newest name, and pronounced it "crips", but said either name was OK. We went with the newest name for 8 months, then my sister said she hated the sound of CRPS, because it sounds like "crypts", and she used RSD. This is completely unscientific and probably kinda silly, but we've switched back to saying RSD now because it doesn't sound as awful, and the disease is so awful that anything we can do to make it even a teensy bit better, we do.