Originally posted by: Cerb
SATA has thinner cables. That is all you need to know.
Is it?
SATA has thinner cables, sure. And better peak theoretical throughput, not that it matters.
A lot of motherboards include SATA RAID support on board, which is handy to some and useless to most. The right drive/motherboard combination would give you little bonuses like NCQ, which to typical users is worth about nothing.
But if you're installing Windows XP (and lots of people do), doing so on an SATA drive often means fiddling with drivers (floppy drives still have a use, after all). And some motherboards misbehave (still) when faced with both SATA and ATA hard drives, which can take a little doing to iron out.
SATA has some advantages. But it also has disadvantages. Both are worth noting. For an average user, the most salient differences are the cables (which may mean better cooling, or may mean being able to place drives farther from the motherboard, or very often may mean nothing), and the sometime quirks of installing Windows to an SATA drive. Which makes it pretty much a wash.
@OP: why do you want a RAID array?