Thermage, Ulthera, Exilis and other similar machines are energy based devices that employ radiofrequency or ultrasonic waves to heat the deeper layers of the skin resulting in skin "tightening". These devices are reasonably effective, especially in persons who are not too heavy and in the 40-60 age range. There is an 85-90% patient satisfaction with the improvement. There is no down time and rarely any complications so it is much safer and less time consuming than surgery, but they do not offer a face or neck lift result.
It is important to understand that Thermage does not replace a neck lift procedure. If surgery is not an option for you, then I believe that Thermage is the next best thing. You can look through some of the before and after photos from the doctors here with many examples of treatment of turkey neck.