What is the comparison between ThermiTight and CoolSculpting?

Very good question. ThermiTight and CoolSculpting use different technologies to produce very different results. ThermiTight is designed to firm and tighten skin in the treatment area. This device delivers radiofrequency energy into the underlying dermal structure to constrict tissue and stimulate the body to produce more collagen. The device does not work deeply enough to reduce fat underneath the dermis. 
CoolSculpting specifically targets unwanted fat. This device uses controlled cooling (cryolipolysis) to freeze unwanted fat cells. The treated cells crystallize and are eliminated through the body’s natural processes. CoolSculpting does not have an effect on skin laxity. In fact, once the fat is removed, loose skin could become more prominent. Some patients benefit from a combination of these two procedures to sculpt and smooth the body without surgery. Make sure the doctor you choose for your treatment is board certified and experienced in the treatment you choose to ensure an optimal outcome. 

CoolSculpting is a fat reduction device. The treatment works through technology known as cryolipolysis or controlled cooling. Since fat cells freeze at a higher temperature than other cells of the body, applying the cooler temperatures to the treatment area destroys fat cells while leaving surrounding skin and tissue intact. The treated fat is eliminated through the body’s lymphatic system in the weeks and months following treatment, resulting in a slimmer, smoother body contour. 
ThermiTight is a skin tightening treatment. This device uses small probes to deliver radiofrequency energy deep into the dermal layers, where it constricts tissue and boosts collagen production. The result is skin that is smoother and firmer in the treatment area. 
While these two treatments perform very different functions, they can work well when combined. I suggest you schedule a consultation with a board-certified dermatologist with expertise in body contouring and nonsurgical skin tightening. Through an in-person assessment, your doctor should be able to tailor your treatment to your precise needs and desired results. 

The procedures you list here offer very different results. CoolSculpting targets unwanted fat, freezing fat cells in the treatment area so they can be eliminated through natural body processes. ThermiTight does not target unwanted fat  - instead, this radiofrequency treatment works in the underlying dermal structure to firm and tighten skin. However, the ThermiTight probe can be placed in the fat to melt it a bit and then I often perform microliposuction at the same time. This allows me to go beyond the limits of the CoolSculpting applicator and both tighten skin and remove fat in the same setting. Since you’ve been disappointed with two sessions of CoolSculpting, I would recommend this combination procedure.
ThermiTight combined with liposuction has been proven to offer the desired outcome, with long-lasting improvement. However, your satisfaction with your results will depend on your expectations and goals. I recommend that you work with a board-certified dermatologist who is an expert in non-surgical body contouring. Through a comprehensive assessment and discussion of your goals, you should come up with a treatment plan customized to you.