The most useful feature is being able to keep track of my income as I earn it (and receive payments). It's also great that they have an option for recurring invoices, so you can set up automatic payment plans without having someone else do all your bookkeeping! There are some bugs with their system - sometimes if there isn't enough time between when two transactions occur or something happens inbetween them then one transaction will be lost somewhere along its way through processing & getting posted/updated into our account. This has happened multiple times now over almost 2 years since we've been using this software but luckily nothing major ever comes out from these glitches because everything gets updated after about 10 minutes later once fixed by support staff at VTVTIO :) They're constantly improving things though which makes me happy =) Very helpful service provider who listens well too what clients want /.