How to estimate import time?

Is there any way to estimate how long an import might take? I know it depends on many factors. All I got scouring the forums is this query which gives an estimate at a table level not at the dmp file level -

select substr(sql_text,instr(sql_text,'INTO "'),30) table_name,
rows_processed,
round((sysdate-to_date(first_load_time,'yyyy-mm-dd hh24:mi:ss'))*24*60,1) minutes,
trunc(rows_processed/((sysdate-to_date(first_load_time,'yyyy-mm-dd hh24:mi:ss'))*24*60)) rows_per_min
from sys.v_$sqlarea
where sql_text like 'INSERT %INTO "%' and
command_type = 2 and open_versions > 0;

Any ideas or did someone has any expertize in this?

Extremely difficult to say. Depends on number and type of indexes, tablespace configuration, import options, order of rows, triggers ...