I own a HAF X. The Antec 1200 was my first choice, but was offered a discount on the HAF X which I could not resist.
The HAF X does afford you a lot of room. Cooling is easy and efficient. I have a nice bit of clearance between my lower GPU and PSU. Good, clean-looking cable management is not a problem. I was also able to fit an H100 (have since switched to a quieter H80) radiator up top with no issues.
I however have to agree that the HAF X is an eyesore: its harsh industrial theme makes the case look like it was cut from a truck's engine block. The Antec 1200 looks sleeker, more elegant, and -- judging from what I had read about it when I began shopping around for a case -- will offer you pretty much everything the HAF X does.
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