Compare these two queries:

select b.prod_name, b.prod_category, a.transaction_amt, a.transaction_dt
  from transactions a, prod_xref b
where a.prod_id = b.id

VS.

select b.prod_name, b.prod_category, a.transaction_amt, a.transaction_dt
  from transactions a 
  inner join b.prod_xref b on a.prod_id = b.id

Is the first query still slower than the second? What are the benefits / disadvantages of using a cartesian join vs an explicit join statement?