The ease of use! It's so simple to make payments with this app as well it has all my accounts set up in one place which makes life easier when I have more than 1 client at any given time (it can be difficult keeping track sometimes). Nothing really - maybe having too many options would lead me away from using them but they are easy enough not matter how much information there could potentially ever possibly need about their service/product being used by another business owner who was happy/satisfied etc..