Clamshell, griddle and open are three different styles of worktop grills. Some grills, such as the Cuisinart Griddler, come with multiple cooking surfaces including flat or grilled.
The Hamilton Beach indoor grill is a clamshell style and known for its quick cleanup. It also cooks food very quickly, similar to the George Foreman grill. According to the TopTenReviews website as of June 2015, reviewers preferred the Hamilton Beach over George Foreman grill in terms of overall grilling capabilities and customer support.
The Smart Planet grill and the Oster Dura Ceramic grill are open grills. The Smart Planet grill received a higher score from reviewers, but it was still much lower than the scores for the Hamilton Beach indoor grill or the Cuisinart Griddler. The Smart Planet scored 5.75 out of 10 and the Cuisinart Griddler scored 9.75 out of 10.
Each type of worktop grill has its own pros and cons. Some types of worktop grills offer a variety of sections with tops that have individual portioned areas, with extra heat for searing meat. Other grills offer more surface area, and provide more splatter protection. Some grills cook exceptionally fast, but take longer to clean up, while others are easier to clean but change the flavor of food slightly due to steaming while grilling.