Which is better: chin liposuction or Kybella?

There are many reasons why Kybella is gaining traction for plastic surgeons.  Surgery is more traumatic and the tissue response to that trauma can result in firmness and skin irregularities in some cases.  Kybella is an adjustable and customizable way to approach your problem and the short term misery with it is really worth the avoidance of surgery.  The first treatment is usually the worse and a few days of visible swelling is expected but your return to society will be quicker with Kybella than with surgery in my experience.  Another good alternative is Coolsculpt mini--very little swelling and discomfort but not as predictable as Kybella

This is a great question that I get asked all the time. 
For almost everyone, I say liposuction.  Kybella is good for patients who have a small amount of fat, that don't warrant a surgical procedure but still want something done to get rid of it.  For patients who have a noticeable amount of extra soft tissue, liposuction is the better choice. 
1- the cost is nearly the same.  At our office submental lipo runs about $3,000 while two treatments of Kybella is $2100.  If you need 3 treatments, the cost of Kybella is more.  
2- cervical lipo can be done under IV sedation, you don't need general anesthesia, so it isn't a huge surgery.  The scar is less than 2 cm long, which is very small. 
3- Kybella does hurt.  It burns going in, and patients are very swollen and red for one week, moderately swollen for the second week.  This happens every time you get a treatment.  With lipo, you are swollen and bruised and need to wear a wrap, but it's only one time
4- With lipo I can be sure I am removing fat, I see it in the canister.  I can shape and sculpt exactly as I want. With Kybella there is less control. 
Overall, if you are going to spend money and accept some downtime to shape the neck, get the surgery that certainly works. 
Best of luck
Dr Rodman