I have a R3. The panels with their sound dampening material do seem to cut down on some low-frequency noise but don't expect miracles. It still depends greatly on the fans you use as they're entirely exposed due to basically having a huge hole in the case.
The only way the sound dampening material would really be effective was if the case was an entirely sealed unit so that no air (and thus noise) could escape.
Airflow is mediocre. The front HDD cage basically blocks the front fans from reaching any further (unless you have high-RPM fans and thus noise). Top, bottom and rear are your main sources of cooling I'd say. Possibly the side too, but again, you're opening another hole for noise to escape.
Quality wise, it has some slightly flaws but nothing too serious. The front is all plastic and the hard drive caddies don't lock in the greatest. They have a tendency to pop out when pushing the cables into the drives.
I have a low rpm Noctua fan on my hyper 212+ in mine. All of the fans are hooked up to a fan controller and slowed down more so. The loudest things is my gts 250 at 33% fan and it's dead silent from 10 feet away. It's great for a HTPC case. As JD said, don't expect miracles. It's simply a quiet case, and you can get a controller to make it near silent.
FYI I have a HAF 912 and I my fan setup only allows for the the unavoidable whooshing of air. It's just as quiet as my past Antec Solo which had sound dampening panels and was an enclosed case, opposed to the 912's open mesh grills. As JD said, it really comes down to fan choice and setup.
My fan setup? 200mm Megaflows, one on front intake and one on top exhaust, running at 50% via BIOS (MSI P67-G43 has four system fan headers all voltage controlled via 25% increments); Scythe Slipstream 800RPM's, one on Hyper 212+ and one on rear exhaust, both running at 100% via BIOS (zero fan noise for these models at 100%); Thermalright X-SILENT-140 140mm side intake fan at 50% via BIOS.
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