Resturant merchants prefer clover due to the rates per transaction. Far more convenient for the merchants than toast and square. Ecosystem wise, Clover has been little by little catching up and improving. They do what they can with the resources provided compared to competitors with over 4k employees. Clover dont get that type of support from fiserv.
On the other hand even if fiserv injects more resources, there are administrative issues where people in Sunnyvale neglect to work with others in different locations and that needs to be checked and rectified. They raised the product, I get it, it is their baby but that attitude hurts the growth of the product and professionally hurts other good Engineers.