What is the best Integrated Library System?

I'm curious to know, what is considered the best Integrated Library System available on the market today? Is there a specific system that stands out in terms of features, ease of use, cost-effectiveness, and scalability? Could you provide some examples of libraries that have successfully implemented this system and the benefits they've experienced as a result? Furthermore, what factors should a library consider when evaluating different Integrated Library Systems to ensure they make the best decision for their unique needs and resources?