It helps in real time calculation without going back into accounting system, it also gives me detailed report with different fields like acc no etc., so I can easily refer those details while preparing my finance reports or submitting them externally as well.
There are few minor bugs but most probably could be fixed by developers if they have enough knowledge about this software & good number of user base. If you're using only one type then there's nothing majorly wrong, however its better option than manual workarounds/workaround since all calculations will get done automatically instead of manually entering each value again after realizing mistakes were made during first attempt - saves lot of precious hours!