The Embody is the most comfortable chair I've used, hands down. I've had one for quite a while and I haven't experienced any creakiness or squeak, and my ass doesn't hurt after several hours of sitting. I tried several Steelseries chairs against it, and the Embody won in terms of long-term sitting comfort.
I'm guessing that if you are over the weight limit, that is most likely contributing to the chair falling apart at such a quick rate. Have you looked into a Herman Milller Aeron? They make them in three sizes, so the biggest size might be more suitable for your body type/weight. They are quite durable chairs, and actually pretty comfortable. I had one for about three years before moving to the Embody.