Utility patents offer greater benefits than design patents. Utility patents protect the way an article is used and works. Utility patents also allow many variations of the article to be claimed in one patent, making utility patents much more broad than design patents. Utility patents can also be filed provisionally whereas design drawings cannot.
Design patents protect the appearance of the article. Design patents are usually much cheaper than utility patents and are much easier to obtain. If the main feature of you invention is the ornamental design, then a design patent is all you need to protect your invention.
We suggest you seek advice from a patent attorney to figure out which type of protection is best for your patent.