"In summary", let me point out that the article referred to is addressed earlier in this thread with full explanations of what many of feel is incorrect in that article.
The big thing the guy said, which never is getting repeated in the repeated, repeated, repeated, claims monitors are inaccurate, is that he said that monitors can be inaccurate in because he thought that they were too complicated to get set up properly and when not set right they would not be accurate.
The author then listed how he would set the monitor and listed settings that would GUARANTEE the monitor would be inaccurate, because, IMO, they were very much incorrect.
We have a poster that is intent on making claims that monitors don't work, but he does not have one and AFAIK has never used, installed, setup, tested, or had one in the past either. He "monitors" $2500 worth of batteries with idiot lights.
One of the biggest, and most important, things a monitor will do is show you if your charging system is doing a good job, or in many (most?) cases if it is not doing a good job, or charging your batteries. For that alone, I think the cost of a monitor is worth it, unless you have a very low cost battery setup and can consider them disposable.
The very first post in this thread and the thread itself, were created to show the test I had run to determine what effect poor charging would have on monitor accuracy, so users would be aware that if can't get your batteries charged reliably it is very hard to be able to know how much power you have even with a monitor. It was also intended to generate a conversation of how to use the monitor to understand the charging issues and allow for and/or correct them. These charging issues are real and folks should be aware of them, but they are the cause of inaccuracies in monitors, not the monitors themselves.
I would suggest anyone who is considering a monitor read this and other discussions on this forum thoroughly, and don't fall for the continual "monitors are inaccurate" unsupported statements that are being made without getting the whole story.
I understand this is repeated information, also, but seems to be needed because the unbacked claims of inaccuracy are again being put in this discussion (to get the last word in?), even as the thread was just cleaned up by splitting off the last wandering diversions.