I like that it has everything in one place, from project management to billing invoicing CRM etc all under 1 roof so we don't have multiple systems which can be confusing for our clients! It's not great at this time but they are working hard with us daily to improve their service offering (eg more robust Project Management system).
They do offer excellent support too as you would expect when paying such an amount of money per month!! We use them mainly because its easy access between internal staff members who work remotely. That said i am sure there is another platform out there somewhere better suited than what we currently using. As mentioned above though the main benefit was ease of accessing information across different teams/divisions within my organisation.