I use Koolreports to create reporting in my company's financial loan software. Our backend was already PHP, Mysql and our frontend is still the old google web toolkit. GWT. I have to do very complex reports with very complex Options for the reports. I then send them to our software UI for now in an Iframe until we upgrade our UI to a JavaScript framework most likely React at some point.
If you are going to use the koolreports library you need to be extremely good at PHP and MySQL, HTML, CSS and it sure helps to have at least some JavaScript knowledge for tweaking UI and PDF or Print Exports. Also to tweak the source code that is javaScript wrapped with PHP classes.
They have so many examples and there is nothing that comes close to koolreports in the entire world. Nothing!!!
The library is so elaborate and wraps numerous open source 3rd party javaScript libraries into a php code interface. They can not build out every single interface with every library to have all features of the 3rd party libraries but they do it well enough you can build upon it.
I have been developing using koolreports library for 2 years. What they provide is incredible, but you must still be competent in PHP and MySql and javaScript if you need to add or alter the source code.
There is no other php library that does what koolreports does. The limitation is going to be your programing skills to use it and tie in everything to produce your reports but if you are a competent programmer in the areas I have stated you can easily produce anything under the sun accounting report related no mater how complex. Modules datagrid/Datatables, Core, Cube, chartjs, inputs are what 90% of my reports were built from. Just those 5 library modules and Koolreports has 29 library modules total.