I bought the dark blue, and one of the black holographic ones. The dark blue fits pretty true to size, but the black that I got runs small.  Even with gently handwashing in cold water, much of the shine and color will come off, even on first wash. If you're planning to to wear these for a specific event, don't wear or wash until after your event.
Luckily I bought these for around the house; I love that pet hair doesn't stick to them.