Expert opinions? Which diet pills (appetite suppressants) work the best?

All have dangers. Appetite suppressants are chemicals that cause complex changes in your body's functions. Ultimately they are not good for you. The better way to reach a healthy weight is to maximize nutrition (real food), sleep well, and get moderate exercise. That approach will take longer but you'll be healthier and have results that will last a lifetime. The paleo approach is one of the better ways to go.
Here is a list.. I typically prescribe phentermine, phendimetrazine (bontril), Diethylpropion (tenuate), or phentermine/topiramate (qsymia) depending on each individuals needs, goals and physical history. Remember that while taking prescription weight loss medications, it is important to begin making small behavioral and lifestyle changes such as healthy diet ; exercise for weight loss to occur. Good luck!