Materialized View or table?

I have a table (A) with 750+ million records and another one (B) which is a
summary of information in A containing 30+million records.

Now I wonder whether it wouldn't be better to have B as an indexed
materialized view. Though not often, there will be situations where B has
to be updated.

In the past I avoided materialized views when the result of a query
contains more than about 1 million records. I do not know enough about the
implications for the server's resources to make an informed decision though.

What are the pro's and con's of large materialized views vs. tables in a
case like this?

Regards
Johann
--
Because experiencing your loyal love is better than life itself,
my lips will praise you. (Psalm 63:3)