What medical alert system is the best for the response time and money?

Response time depends on your local Ambulance not the Alert company. When Mom pushes the button an operator comes on immediately. She asks questions to evaluate the situation. If you are first contact you will be called. Otherwise, the operator will call your local emergency dept.

Remember, if there is a DNR, have it where emergency personnel can find it.

There are dozens of alert systems and each of them have their fans and detractors. Remember that these are all just essentially a way to call emergency responders if a person lives alone and suddenly becomes incapacitated, they can not take the place of human eyes and ears when someone isn't safe to remain alone.