Okay, here's my take (its all about numbers)

At 70,000 miles you would change the oil four more times by using the 5K plan. Changes are pricey, mine are $80. So its $320 difference in the first 70,000 miles.

I don't think 320 is too much to spend for a little peace of mind. And, 70,000 miles may not be 7 years like the warrenty implies, but if you DO only drive 10K a year its only a $46 a year (less than $4 a month) difference. Heck, that's a good deal at twice the price!

Change em at 5K. It may be under warrenty, but do you want to go throught he hastle if 7K isn't quite often enough?!?