Welcome gristchi!
I recommend that you do some research on the various diets. Check out the forums for each, and feel free to post plan-specific questions. What is the best plan for you? Only you can answer that question. How does your body handle carbs? Protein? Whole foods? What are your trigger foods that you can't seem to limit?
Pick a plan that you can stick with for life - one that will train you to develop healthy habits that you can live with long-term.
Personally, I count calories. I try to practice portion control, eat every 2.5 - 3 hours and eat as many non-processed and whole foods as I can. I feel so much better when I eat this way, and eating every couple of hours really helps me keep my emotional, stress and boredom eating under control.
For me, exercise is also an important part of my plan. It helps me feel strong and fit and keeps me feeling positive about the changes I am making.
For the first time in my 49 years, I think I CAN do this for the rest of my life.
Good luck! You CAN do this.