Chip-wise/GHz's , PIV's are cheaper.
But, you need a different power supply - motherboard depending, and the RAM is twice as much.
So, in the end it evens out in price between P4 and P3. It's close.
mauibaja, I doubt you will have many problems if you bought it recently(even if you didnt, just may need to do a bit more troubleshooting, but that's par for the course). It's typical for new products to have problems. But, the PIV isn't new anymore, just maybe not the exact choice at the moment. It changes fast. If it's doing what you need it to do at this time, run with it.