INSERT /*+ APPEND */ a good idea ?

Sometimes , sometimes not
1) not good for many small inserts as it appends each insert above the high water mark, leaving lots of unused space
2) only one session at a time can do it at a time

see
http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:1211797200346279484