truncate vs. delete - Mailing list pgsql-sql

Good morning,

If I remember correctly, "delete" does not release space, while truncate 
will.

I have an option now

(1) Use object creator(with create/drop permission which I do not need 
in my cronjob script) to truncate table1(>100,000 recs) records

(2) Use user1(has r/w only) to delete from table1, then vacuum it

May I know how inefficient "delete from" comparing to truncate please?

Thanks a lot!