Simulring buys a batch of numbers from a phone company. When you sign up, they assign you one. When somebody calls that number, all your phones ring at once. Whichever phone you answer takes the call. It's easy to set up.
Many powerful technologies force users to endure lengthy learning curves.
Simulring takes a few minutes at most. Score one for simplicity. It rings all your phones. One reason I have multiple cell phones is because I travel a lot. Some have good coverage in one part of the globe, some in others.