I like that it can be used both by myself or other people in my office, we've been able use this software since our last accountant left us so there was no one else who could do as much work! It's not very user friendly but once you learn how easy/hard something might seem at first its really simple when working through each step of creating an invoice etc..
The best part about using FMAnger though out process has helped me keep track more accurately what bills need paid vs just paying them off hand which sometimes gets forgotten during busy times!!