I like most of all, how simple it is to use! You do not need any technical skills or previous experience in trading before using this software; you just have an account there (no matter if its free one) - then go ahead creating new orders/invoices etc., without having much knowledge about what needs doing where exactly as well when they are created at first time. They support many types e-payment methods so payments look good too after being invoiced from their side via API integration into my system which helps me keep track easily even though i dont receive paper checks anymore but electronic ones only instead since years now :) The best feature would probably be auto export functions between those three major systems we're dealing here (TradeDesk / CXO ERP & Xero). No more manual exports needed ever again ;).