Guess that depends on what you're putting in it. The CM690 only supports up to ATX size, while the HAF X will also accomodate E-ATX, which many mobos are - more so when Haswell gets rolling real good. Also the CM690 has less airflow and fewer expansion slots. These things may not matter for the build you're planning now, but if you'd like to purchase a case that'll support current hardware, as well has hardware many years into the future without worrying about a case upgrade, go for the HAF X.