Either will work fine for a sub. The AES3 cable has controlled 110-ohm impedance for digital audio. The other is designed for analog audio.
You can have a cable made up to your specs with Mogami W2549 mic cable and gold Neutrik XLRs for about $70 by ProAudioLA (and probably many other pro-audio shops). This is the premier mic cable by a premier cable manufacturer. For a few bucks more, you can have colored rings added to the connectors to identify it to you as the sub cable. It will be just as good as the $170 "Gold" version that is pre-made.
You can have a cable made up to your specs with Mogami W2549 mic cable and gold Neutrik XLRs for about $70 by ProAudioLA (and probably many other pro-audio shops). This is the premier mic cable by a premier cable manufacturer. For a few bucks more, you can have colored rings added to the connectors to identify it to you as the sub cable. It will be just as good as the $170 "Gold" version that is pre-made.