If you are looking for a basic entry level camera I recommend an 35mm Single Lens Reflex, (SLR). There are many, the vast majority are very capable cameras with decent lens. Nikon FM or the second generation FM2 is an excellent camera, others manual focus cameras to consider are the Pentax 1000, or MX, Minolta 101 to 301, Canon FTB, Olympus OM1. In terms of auto focus, Canon Rebel, Minolta 600SI, or Nikon N90, just to name a few. Don't spend an arm and a leg, you need a camera that can be set to manual, lens are not too expensive, and relative reliability, Start with a standard 50mm or zoom in the 35 to 70 range, shoot some film, have it developed, have enlargements printed so you really look at your work on the wall. Read about the art of photography, composition, capturing the decisive moment. Once you get your feet wet you will begin to figure out what you like to photography you will figure out what kind of system will best suit your needs.
To answer your question, I not sure what 4 cameras you are asking about.