What do you like best?
It is a well designed billing system you can use in different business type like professional service. It is easy to be installed to your salesforce org and only need a little configuration.
FinancialForce also provide a timely support to its customer to make issues solved in time.
What do you dislike?
It is very easy to use since it is built on salesforce platform, but at the mean time, their are several restrictions on the platform. So it maybe hard to debugging errors because you cannot make sure which system the error encountered.
Another drawback is that their are some performance issue when billing a bunch of stuffs. I believe this is also caused by restriction of salesforce, but it is really a pain point for me.
What business problems are you solving with the product? What benefits have you realized?
We use this to billing our professional service invoice, we use timecard as billing materials and billing out to our customers. This product suit our business logic very well and we can use it with almost no modification. This saved us a lot of time to start our business.