Hi!
I'm not sure if it is possible to say one technology is "better" than another. However, here are some useful points to consider (and bear in mind that I have tried them both in my practice):
The VASER uses ultrasound energy, which when properly applied to the tissues, is highly specific for fatty tissue emulsification. This means that nerves, blood vessels, and skin are at low risk of injury—a great benefit. The blood supply to the skin and other tissues is minimally disturbed—and this is evident in the material removed during the procedure; the amount of blood seen in a VASER case is remarkably less than in liposuction cases where other technologies are used. VASER probes are blunt and at least 2.9mm in diameter, so the risk of penetration of the abdominal wall is quite low in the hands of a well-trained and experienced plastic surgeon.
The laser-assisted technologies uses laser frequencies that are not as specific for fat as the ultrasound energy of the VASER is, meaning that the energy emitted from the device can be nearly equally damaging to fat, nerves, blood vessels, and skin. The company says this is a benefit, as the device will coagulate blood vessels so there is less bruising; but as a plastic surgeon, I think that preservation of the nerves and blood vessels is in my patient's long term best interests considering that there is very little bruising with the VASER in any case. Finally, the laser filaments are narrow, pointy, and the tip gets quite hot—I am concerned that this creates a significant risk of penetration of the abdominal wall, leading to bowel injury upon skin penetration.
The final remaining point to make is that the companies that produce laser assisted liposuction devices claim that these devices are a patient's best option because of the promise of "skin tightening." This improved skin tightening over other techniques (including the VASER) has simply not been seen by any responsible and unbiased practitioner or in any well done and honest study.
So, in my opinion, the laser assisted devices offer no advantage over the VASER, and expose the patient to significant added risk. That's why I now have only a VASER and have gotten rid of my laser assisted device.
I hope that helps.