I think Beyond covers the basics very well and gives you lots of ideas on how to customize your template.
5/3/1 alone is not a program, it's more of a method to apply to lifts. Learning how to customize the templates becomes the program.
Forever seems to have a whole bunch of NEW stuff which, while REALLY cool, might not possibly be easy for people just starting out and learning to program. Which is fine because there will likely be lots of programs that you can do as is, but it's once you start tweaking that the real understanding starts.