Liposuction can be a very effective tool when used by the a well trained person and for the right indications.
Your weight should not exceed 10% of your ideal body weight if you are considering liposuction. Remember that liposuction is NOT an alternative to diet and exercise.
Several liposuction techniques exist on the market: Suction assisted liposuction or SAL, ultrasonic assisted liposuction or UAL, laser assisted liposuction, and radio frequency assisted liposuction.
Before opting for any of the above techniques, you should know exactly its advantages and disadvantages as well as its potential complications. Some are new on the market, but pushed very hard by some surgeons with a very aggressive marketing. The results are some times disappointing if not purely disastrous. That is why it is very important to read and research ahead of time. The more information you have, the better the choice you will end up making.
One more thing: You should always make sure that your surgeon IS a plastic surgeon who is well trained in the technique he wants to use.