It is generally better to bake pork chops covered, as this will help them retain moisture and prevent them from drying out.  The lid of the baking dish or pan traps steam released from the pork chops and keeps them from losing too much moisture or becoming tough.  When cooking pork chops that have been marinated, covering them helps to preserve the flavors of the marinade and seasonings.  It also prevents potentially harmful splattering that could occur when baking uncovered. The only time you should consider baking pork chops uncovered is if you are trying to achieve a crispy texture.  In this case, using a broiler can give you better results than baking in an oven.  For best results, use a high-quality cut of meat with plenty of fat content so it does not dry out while cooking.  Additionally, patting the pork chop dry before putting it in the oven ensures more even cooking and crispiness all around.