I've read makers of companies recommending the pink stuff almost always. In a northern climate, it doesn't take much water in a joint, valve, or other fitting to crack it.
In southern climates, you can get away with not being meticulous about winterizing. For example, I've used cheap vodka through the lines, then blown them out with air, which means that any water in the system usually has some alcohol in it, lowering its freezing point. However, I wouldn't recommend this because I'm doing this at my own risk.
When in doubt, go with the pink stuff. Far cheaper than hunting down and fixing a cracked pipe or fitting.