What does the company do well? One of the lowest cost online payment processors around.
What does the company not do well? Nothing comes to mind, but you should do your own analysis to make sure you have enough volume to offset the monthly fee. Take that into account when looking at your cost per transaction.
What do you wish you had known about the company before using? That the monthly fee would be on a separate bill. It would be easier if it were all on one invoice.
Have you used a competitor to the software or service? If so, how does it compare? Yes. Fattmerchant is vastly superior.