Lots of variables. There are many different types of dentures available these days. Traditional dentures to those held in with implants. Expectations will be different for each type and each person. See a well qualified dentist for a complete evaluation and consult for what will work best for you. Good luck.
Dentures or ? These types of questions are best answered by seeing a local qualified general dentist or prosthodontist who can go over your medical and dental history, clinically examine you and take x-rays of your mouth. Then treatment options can be discussed as well as pros and cons of each choice, prognosis, and what to expect. Doing anything less is shortchanging you and a bad idea!
Reduced function. While dentures can be made to resemble a set of natural teeth, dentures will at best restore your esthetics, but at best give you limited function as they rely on suction for stability. The upper suction is generally ok, but often the lower has poor suction resulting in poor stability. Expect a nice appearance and difficult eating.