BigQuery filter using LEFT OUTER JOIN or Anti-join

Question

I can think of 2 methods to filter in Google BigQuery. (Say Table2 is small.) Which method of filtering would be preferable, and why? Does it depend on the size of table1? Or is there another, better method?

SELECT
  a.ID
FROM
  table1 AS a
LEFT OUTER JOIN
  table2 AS b
ON
  a.ID = b.ID
WHERE 
  b.ID is NULL

or

SELECT
  ID
FROM
  table1
WHERE
  ID NOT IN (
    SELECT
      ID
    FROM
      table2)

Answer 1

Second is limited to one and only one field to be filtered by.

First can be used to filter by multiple fields, like below

SELECT
  a.ID
FROM
  table1 AS a
LEFT OUTER JOIN
  table2 AS b
ON
  a.ID = b.ID AND a.Field2 = b.Field2 AND a.Field3 = b.Field3
WHERE 
  b.ID is NULL

Answer 2

I tested a two fields anti-join and the difference was noticeable.

SELECT fields, ..
FROM inputA A
LEFT JOIN inputB B
  ON A.key = B.key AND A.key2 = B.key2
WHERE B.key IS NULL AND B.key2 IS NULL

Performs better than its NOT IN equivalent:

SELECT fields, ..
FROM inputA A
WHERE key NOT IN (SELECT NUM_RUT FROM key)
  AND key2 NOT IN (SELECT key2 FROM inputB)

in this case 5s vs 7s in BigQuery after reading 4.6Gb.