So the quick answer is that paying cash rules on both fronts.
While the employee discount is one price, the value of my trade-in magically increased $1500 with cash.
However, in the end, I bought a used SEL hatchback with only 18,000KM, and every option except Nav.
The car is 6 months old, and it devalued 30%. The dealer could not sell the car, because of the 0% purchasing right now at Ford, versus the 5% on used vehicles. Right now the average Canadian is so far in consumer debt, people are really only buying with 7 year financing.
0% is a gimmick, the interest may be "zero" but the purchase price is higher.
So the experience is the same as I had in 2003, it really makes sense to buy a used current model year car, not new, the difference is that you let someone else take the 30% haircut. Also, all those options that drive up the price on a new car are only worth a fraction used.