They're both made of wires, so theoretically they will be equally reliable (assuming equal wire quality). As for the connectors, I have experienced 0 of the problems that have been brought up about SATA cables. The SATA cables are obviously going to have a less snug fit than the PATA (which has LOTS more pins to connect to). However I have yet to unhook one of my SATA drives accidently while poking around in case (not that I do that much when the computer is on anyways

).
As for the size, you can't beat the SATA cables, yes the standard cables don't bend at 90 degrees, but they are loads easier to route than PATA cables IMHO (even rounded ones).
Edit: Here's an example of the ease of routing.
Case
Antec P160
Asus A78NX Deluxe
Seagate 120GB
Seagate 200GB