"protect yourself from being taken advantage of by unscrupulous competitive suppliers or brokers by understanding your choices and knowing your rights as a consumer"

The Massachusetts Office of Consumer Affairs and Business Regulation has a good post on how to understand the electricity marketplace and make good decisions. 

They provide a list of questions to ask to help set up a proper comparison of the rates and services so you can make a good choice.

Massachusetts Office of Consumer Affairs and Business Regulation

"Comparing Plans

Although promotional offers may be appealing, there are a number of factors that may affect the amount you will actually end up paying for your electricity.  It is important to review your options and compare them to the local utility company’s basic service before switching.  Asking the following questions can help you make an informed decision.

1. Are the energy prices (rates) fixed, or will they change throughout the term?  If your energy consumption is consistent, fixed rate plans will offer less variation in your monthly bill.  Variable rate plans, however, fluctuate more often because the rates can change by the hour, day or month, etc., according to the terms and conditions in the competitive supplier’s disclosure statement.
2. What is the length of the contract?  Consider how long you will be locked- in to the contract and what that means in conjunction with the rates.
3. Is there an initiation/transfer charge?  If there is an initiation fee, you could be paying more.
4. Does the contract contain an introductory price?  If your contract contains an introductory price, then your supply cost may increase substantially after the introductory pricing period ends.
5. Are there minimum bill amounts?  If so, consider whether you consistently use the minimum amount of power.
6. Are there cancellation fees?  Consider whether you will have to pay a cancellation fee or other fees at cancellation whether or not you terminate the contract before its expiration date.  It is common to pay early termination fees if you cancel the contract before it expires.
7. How does renewal work?  Consider that if you do not make a decision to renew or cancel a contract within the permitted period the competitive supplier may renew your contract and change its terms.
8. What is the price per kWh?  Calculating your usual monthly kWh consumption times the price per kWh will help you compare supply cost.
9. What is included in the price per kWh?  If you can find out how the company sets its rates, you can make a more informed decision."

You can read the full article here
http://blog.mass.gov/consumer/massconsumer/competitive-energy-sellers/