Given its small size, having four PCIe connectors, six SATA connectors, and three Molex connectors on the Seasonic FOCUS SGX is no mean feat.  That will give almost any SFF build more than enough power, or even a full sized build if you prefer a small PSU for whatever reason.  The 10 year warranty indicates Seasonic has a lot of faith in this unit, and [H]ard|OCP's testing shows it is deserved.  You will pay a little more for the FOCUS SGX but in this case it is actually worth it.

"Seasonic is FOCUSing more on small footprint high output power supplies, and the new FOCUS SGX series is targeting the small form factor market once again. This beefy 650 watt unit is fully modular, packs a 10 year warranty, is diminutive in size, had good efficiency, and comes complete with an ATX adapter plate as well."

Here are some more Cases & Cooling reviews from around the web:

CASES & COOLING