Performance Tuning :: Create Versus Rebuild Index

I was comparing cost of rebuild vs create index...I carried out the following test

SQL> create table t4 as select * from t1;

Table created.

SQL> create table t5 as select * from t1 where 1=2;

Table created.

SQL> create index i5 on t5(id);

Index created. SQL> select bytes,extents,blocks from user_segments where segment_name='I5';

BYTES EXTENTS BLOCKS
---------- ---------- ----------
65536 1 8

SQL> alter index i5 unusable;

Index altered.

SQL> alter table t5 nologging;

Table altered.

SQL> Alter session set skip_unusable_indexes=True;

Session altered.

SQL> insert /*+ append */ into t5 select * from t1;

563904 rows created.

SQL> commit;

Commit complete.

Now I compared the cost (elapsed time, logical I/O) of the operations

create index i4 on t4(id);
Vs
alter index i5 rebuild online;

Following is the related trace of above 2 steps

create index i4 on t4(id)

call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 1 0 0
Execute 1 1.17 3.38 9497 7869 335 0
Fetch 0 0.00 0.00 0 0 0 0
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 2 1.17 3.38 9497 7870 335 0

Misses in library cache during parse: 1
Optimizer goal: CHOOSE
Parsing user id: 5
[code]....

So which option we shall pick in such cases? {Of course I haven't set 'nologging' for the indices but it is same for both indices we are comparing}