I agree that the simple charge controller switching off at 14.2v is not wonderful.  I wouldn't want the thing to drop to 13v before coming back on, but all these things require manual intervention and a good equalising charge regularly should keep things under control. At least with flooded cells it is possible to keep an eye on sg.

Without common sense from the user there is always a problem, some systems take little out of the battery, some drain it regularly, some sit near floating for weeks and then take it well down at a time when there is no power available to charge it. Just relying entirely on any controller is not without its problems.

I was trying to give him some idea of the difference between guessing state of charge from volts and what is required to actually charge it. Sadly if he looks up the care of batteries the information is still rather conflicting. Controllers seem to have got better over the years and that seems to have let battery manufacturers produce things that work as well at lower cost but they are certainly not as robust as older ones. I don't see batteries lasting longer now than 40 years ago but they are cheaper lighter and certainly cleaner.