I have another pair of basic black rectangular Marc Jacobs shades I bought last summer. Sadly, I am constantly pushing them back up my nose as they slide down every time I move my head or look down. This pair is quite the opposite: lightweight, colorful, stays in place and has great coverage from all angles. Another consideration was the fact that the lenses do not squash my eyelashes as many others do, which is a definite deal-breaker.
Overall I am hugely happy with my new purchase, particularly because they match my nail color of the moment, though I will continue to adore them long after my polish has chipped away.