Both have its advantages and disadvantages.  If you are bothered about looks , go for ceramic but the elastics or modules would turn yellow with turmeric by the end of the month if not properly maintained. Ceramic the lower range ones may be brittle, ask your orthodontist for details. If you dont mind a metallic smile, go for metal self ligation. They dont turn yellow.

Conventional self ligating ceramic bracket like 3M is always better.

If you are cosmetic conscious go for ceramic braces . Self ligating braces are recently most advanced braces available