They tend to force many ingredients into one tablet trying to convince the consumer that their needs are met in one magic pill. Very few companies have mastered the proper technique of tablet making. Liquids supplements are easy to absorb but require heavy dosing in order to achieve desired RDA allowances. They are cumbersome when traveling and tend to taste unpleasant. Often the taste must be disguised by some type of sweetener.
Some sweeteners are harmful while others are perfectly acceptable.
Know which sweetener is in the products your considering. Capsules tend to be the industry's favorite. The capsule is usually made of gelatin allowing easy breakdown of the nutrients inside. For the vegetarian there are capsules made from vegetable sources although they tend to cost more. Like tablets capsules can have fillers.