Answering a few of the questions so far:
1) Aftermarket GPU coolers: We try to avoid using them, but we have in the past. Many require heatsinks to be attached to the video RAM with thermal epoxy. A warranty nightmare. Overall we are very pleased with the Asus DirectCU line!
2) Fan control: The fans are all PWM, controlled by the BIOS. We don't want Windows-based software controlling them, because we don't want the Serenity experience to be OS dependent. We see a strong Ubuntu demand here! We work with Asus to custom tune the fan response curves, with two goals. First, obviously we reduce the RPMs. Stock BIOS would throw fan error warnings with how slow we run the fans. Second, we tune the fan response time. When dealing with lower airflow like this, you can encounter...what would you call it....thermal resonance? The fans endless cycle up and down, up and down in RPM trying to respond to a changing chassis temperature. Hundreds of hours of testing time have gone into tuning these things.
3) Fan attachment: We attach with screws. Things like fan vibration dampening, PSU mount vibration dampening...its more gimmick than useful feature these days. The only things we find still have the ability to create vibration in the chassis are the optical drive and platter hard drives. The system fans and even CPU fan run too slow, and are too well balanced, to create any noticeable vibration.
4) Build your own: We certainly won't stand in the way! In fact, we try to be as transparent as possible with our process. That's one of the things I enjoy most about Puget Systems -- we're not trying to hide behind "proprietary information" to keep ourselves in business. What we do is the result of good old fashioned hard work, and LOTS of time perfecting our trade. We embrace the enthusiast and DIY community. We're actually not even targeting those folks to buy our PCs -- we know you can do much of this on your own. But we also know you are likely the "computer guy" to your friends and family, and we want to be the trusted source you can refer those friends and family to!
The "picked by ear" concept is probably the strongest feature that sets us apart from DIY. The custom BIOS tuning with Asus is another. These are BIOS customizations that Asus is not comfortable putting public, because there are many who would use it incorrectly and lead to higher failure rates on their components.