A great add on feature would be the ability for each service provider to be able to collect money with their own PayPal account.
Also, some service providers might want to collect a fee online and others may not. I'm looking at providing a system for 20 plus fishing vessels. Some may want to approve their own appointment requests manually without taking down money and others may want to take down money and instantly allow the time slot to be booked.
I'm guessing my situation is not unique.