What is the difference between Nova Thread Lifts and Silhouette InstaLift? Same product, different manufacturers? Is one better than the other in terms of efficacy, longevity, cost, safety? Or are they essentially interchangeable? Do they target the same facial areas? Are they just a matter of preference, like dermal fillers, when someones chooses a hyaluronic acid filler like Restylane over Juvéderm?