Squirrel king, welcome to the forum. Glad you decided to speak up.
Depth varies greatly, depending on the metal of the buried object, the size, the condition of the soil, and the quality of your batteries. Also, headphones make a big (positive) difference when detecting. Most would say the Minelabs have the best depth, but that is a matter for some debate. You really should ask yourself which areas you'll be detecting in, what your budget will allow, and how much detecting you'll be doing. Then you will want to determine which machine is best for you - regardless of depth.
It seems to me the Tesoro Umax machines are popular for hunting relics. I use a Tesoro Lobo Super Traq, which is known for its nuggetshooting abilities, but which works well as an all-around machine for me. For others, they might have other preferences. It's a lot like cars, loyalty is strong in car owners - and detector owners.