Both Insurance Agents and Insurance Brokers sell insurance to people who need the insurance but the Insurance broker is a person who represents consumers in their search for the best insurance policies that fits that persons needs.
The insurance broker works more closely with their clients to research the insurance coverage for the person and ensures the person who is buying the insurance understands the terms, conditions, and price and then recommends the best insurance policy for the person.
An insurance agent basically sells the insurance and represents either one or more companies.
An insurance broker is usually more expensive for buying insurance through while an insurance agent usually can get you cheaper insurance because they do less work than an insurance broker.
For an individual going through an insurance agent is usually the best but for company insurance going through an insurance broker would usually be the best.