BFG did a good job engineering the BFG ES-800 power supply. A big part of that can be attributed to Jon Gerow aka JonnyGuru who recently joined BFG's team to work on their power supply line of products. In our testing we saw an amazing efficiency of 84.9%, which is most probably a result of the "Frequency Conversion Technology" in this unit. I am confident there are other load scenarios where the PSU can easily break the magic 85% mark. All three voltages showed good stability in our load test, the ripple voltage was also low.
For a price of around $200 you will receive a well rounded power supply that uses unconventional engineering on the inside, which is paired with a high build quality on the outside. BFG includes a lifetime warranty which suggests that they trust the build quality of their PSU to not fail you any time soon. The only things I can put my finger on is that the power supply is not modular, which is very useful to keep your case inside cabling clean. According to BFG the reason for the fixed cables is that Ultra claims a patent on modular power supplies, so BFG went with fixed cables to avoid a potential lawsuit. Also the fan, which I would call "quiet", tends to run louder than other PSUs we tested before (in a similar performance class).