I have four detectors, the oldest is 37 years old and the newest 6 years old. The oldest is by far the best detector that I have ever used.
1 - 1976 A.H. Electronics Super Pro 2 body mount. Its discrimination ability still leaves most of the new models in the dust. I hunt right behind people using new top dollar detectors and find more than they do. Except when using all-metal mode it lacks the depth of the new detectors but in this area coins are hardly ever found over four inches deep and it reaches 5 or 6 inches in discriminating modes. Excellent pin pointing ability. With this detector, you don't have to have a pin pointer. And you can use it comfortably all day long.
A.H. Electronics stopped making detectors about 1980.
2 - 1979 A.H. Electronics Super Pro 5. Good detector, excellent discrimination. Not as good at pin pointing or depth as the Super Pro 2 but better for finding nickels. It is too heavy for long hunts.
3 - 1980 Garrett ADS 3 with co-planer coil. Good depth, good discrimination, easy to use but harder to pin point with.
You need a good pin pointer with this detector. Too heavy for long hunts.
4 - 2007 Garrett GTAX 500 good detector with target ID and depth. Excellent for relic hunting. It has good depth but iron discrimination has a lot to be desired, especially when objects are very rusty, and its pin pointing ability is not great. Continual beeping is hard to live with until you get used to it.
I think either an E-Trax or AT pro is in my future before too long.