Does anyone know whether the XML or T-SQL count() functions are equivalent in execution, or is one more efficient than the other.

Is there any significant difference between...

SELECT

@max-2 = @x.query('

{ count(/Employees/Employee) }

').value('e[1]','int')

and

select @max-2 = count(*) from

@x.nodes('/Employees/Employee')

e(x)

?

The query plans indicate that the cost of the first is twice the cost of the second. Is this true in practice?