Optimal SQL

Please excuse what is probably a no-brainer, but here goes.

Is there any difference, in terms of performance or any other pertinent
factor, between:

SELECT * FROM tblCustomers INNER JOIN tblCustomerOrders ON
tblCustomers.fldCustomerID = tblCustomerOrders.fldCustomerID

and

SELECT * FROM tblCustomers, tblCustomerOrders WHERE
tblCustomers.fldCustomerID = tblCustomerOrders.fldCustomerID

I note that if I type the latter into the SQL pane in a Data window,
SQL Server replaces it with the former.

TIA

Edward
--
The reading group's reading group:
http://www.bookgroup.org.uk