SAP PS Question:

LSMW is an encapsulated data transfer tool. It can provide
the same functionality as BDC infact much more but when
coming to techinical perspective most the parameters are
encapulated. To listout some of the differences :

LSMW is basicaly designed for a fuctional consultant who do
not do much coding but need to explore the fuctionality
while BDC is designed for a technical consultant.

LSMW offers different techinque for migrating data: Direct
input ,BAPI,Idoc,Batch input recording. While bdc basically
uses recording.

LSMW mapping is done by SAP while in BDC we have to do it
explicitly .

LSMW is basically for standard SAP application while bdc
basically for customized application.