Your safety and outcome are going to depend on the education, training, experience, and skill of the surgeon you choose, and only minimally on the machine they choose to use.
Please understand the following:
Tumescent liposuction, VASER Lipo, Smart Lipo, Cool lipo, Pro Lipo, Slim Lipo, Body Jet lipo...
What does this all mean? If I don't get Smart lipo does that mean I'm dumb? If my surgeon recommends Slim Lipo does that mean he/she isn't a "Pro"? It truly is a ridiculous situation we have come to with regard to liposuction and the number of people trying to cash in on America's desire to be rid of its collective fat.
In well motivated patients, body contour improvement can be a very healthy endeavor, but how is an otherwise intelligent and well-adjusted person to know the difference between a responsible provider of aesthetic services offering them safe options for help with their body contour and a poorly trained and inexperienced provider more interested in their wallet than in your outcome and safety?
It is first important to realize that all of these devices will require you to undergo a liposuction procedure. The only difference is the approach to the treatment of the fat prior to its removal.
Because they all involve liposuction, and this is in fact a surgical procedure, it is very important that you "do your homework" and find a surgeon certified by The American Board of Plastic Surgery who has the years of training in liposuction necessary to give you the safe experience and superior outcome you deserve and desire. Behind the amazing number of machines now available to remove your fat, there has followed an army of their sales representatives and an equally impressive number of providers marketing themselves as "liposuction experts".
What has made them "liposuction experts"? In almost all cases, a few days or weekends training with the salesman for the device or with someone more experienced in the procedure. It is their promise that if you have the device in their possession brought to bear on your behalf, your fat will be gone, your skin will miraculously shrink away, you won't need any anesthesia because the device allows painless removal of the fat, and it can be done on your lunch hour. The only thing I am surprised by at this point is that they don't promise you'll get rich and be more sexually alluring after the procedure too.
Selling the particular device to patients is not unlike someone saying to you that because they will give you access to Tony Stewart's racing car that you will be able to win this weekend's race and make a million dollars. Tony Stewart wins races because he is a great racing car driver AND he has a great car...This is no different.
Getting the best outcome from a body contouring procedure depends most on finding a well-qualified and experienced surgeon, and much less on the device used.
Most of these people are so aggressive in their marketing of these questionable devices because they are, in fact, not trained plastic surgeons but rather are either not physicians at all, or they are doctors with core training which would not have prepared them to do liposuction. Many have read recently about a death in my home state of Florida after a healthy 40ish year old mother had liposuction performed by a rehabilitation medicine doctor. Amazingly, I know of eye doctors (!!) doing liposuction as well- and yes, they market themselves as "liposuction experts".
The particular device used can affect the overall experience, however.
Despite the claims of the manufacturer and the practitioners who plunked down the large sum the device costs, Smartlipo has never been proven to shrink skin better than tumescent liposuction. SmartLipo, SlimLipo, Prolipo, and Coolipo all use a laser to destroy the fat cells, allowing them to be removed by liposuction. My problem with these is that, first of all, as a scientist and doctor I am offended when false claims of benefit are made, and that because the lasers will burn whatever you point them at, I worry that your nerves, blood vessels, muscles, and skin may be injured by the laser.
Bottom line (and in my opinion) -- there is no benefit to these devices, they are expensive (meaning that the cost to you, the patient, will be higher as well), and the risks are higher.
Tumescent liposuction is the gold standard to which all other techniques must be compared. It has been proven to be safe and effective over many years (provided that it is performed by a well-trained surgeon). It involves the injection of a fluid into the fatty tissue layer that causes blood vessels to shrink and the fat to expand, making it easier to remove and lowering the risk of a complication.
VASER lipo involves an additional step, in which the fat (after injection of fluid but before suction is applied) is treated with ultrasound energy. Unlike the laser filaments used in SmartLipo and the other devices mentioned above, the VASER probe is blunt and the ultrasound energy it uses is much more specific for fat, so that the risk of injury to the blood vessels and nerves, as well as the muscles and skin are much lower. This is seen in the patient experience of reduced swelling and bruising.
Each time a new (revolutionary!) liposuction machine comes out, I think the most important questions to ask are not "Does it work?", but rather, "Does it work better than what is already available, is it less expensive (not more), and is it safer than what is already available?"
The VASER (in my opinion) passes this test, while the laser based devices do not.
Having said all of that, I would emphasize that it is the education, training, experience, and skill of the surgeon at the end of the liposuction device that will make the greatest difference in your outcome and safety. There is not substitute for the years of training Board Certified Plastic Surgeons receive in liposuction, directly supervised by other Board Certified Plastic Surgeons. A well trained and Board Certified Plastic Surgeon would be more than capable of achieving a better outcome through tumescent liposuction than any eye doctor with a Water Jet. As in the analogy of Tony Stewart above- a great professional with a great tool (like the VASER) would only make those results and their safety even greater.
Please know that I have no financial relationship with any of these companies and have personally tried each of the discussed technologies myself on patients.