The ease of use, how fast it updates itself in order to stay relevant and up to date as far as changes go. I don't like that you cannot have multiple users per account or add additional storage areas (such as trucks) without paying extra.
If your organization has more than one shipper then this should be no problem at all! It's not easy finding an accurate solution out there when dealing with so many different carriers/shipping companies. With Shippers Edge we are able to easily track shipments