Wafer head Floor Screws Self-threading or Self-taping?

[Re-Pete]

I'm replacing my entire sub-floor.

My original sub-floor was held down with Philips head self-threading wafer head screws. Has anyone replaced the sub-floor self-threading wafer head screws with self-tapping wafer head screws. I'm also looking for sources for quality wafer head screws. Out of Doors Mart has both kinds. Self-threading are 69 cents each and the self-tapping are 23 cents each. Big difference in price for some reason. I'm inclined to use the self-tapping because I won't need to drill then screw, but I'll do the extra work if the self-threading are better. Since I need about 100 I want to purchase the right kind and get good quality screws.
Thanks