There's not going to be a whole LOT of difference between the two, although the AHCI protocol used for for SATA includes some additional performance options that IDE doesn't support. For new systems there really is no reason to use IDE, it's there solely to support older hardware or software drivers such as those included in Windows XP.
Warning - if you installed Windows with the BIOS configured in IDE emulation mode, switching to AHCI (SATA) mode will render it unbootable. There's a relatively easy fix for this which I can post if you need it.
If you have the choice choose SATA. IDE is a dying interface.
Wrong. There is a huge market for IDE replacement SSD drives in older computers, especially laptops. The performance increase will be considerable for any software which requires overlaying from RAM to mass storage.
Want a faster machine? Happy with what your existing one does? Slap in an IDE SSD.
Companies like OWC recognise this with their IDE/ATA SSD.