jimmysmitty :
I personally think build quality is the most important part. This PSU has a lower grade build, less warranty but hey it includes an out dated adapter and you can hook up two higher end GPUs to it so it rates the same.
I personally don't feel like the two PSUs are in the same class nor deserve the same rating. To each their own.
In regards to build quality, the SX650-G is no less than that of SF600, besides the bulk cap being lower in temperature rating at 85C (which itself is a high quality brand and part btw, and we do extensive testing to make sure cooling is sufficient for it to last), everything else on the PCB is on par or better. And besides the core components,
we've shown over at jonnyGURU, the fan we used in SX650-G is definitely better than SF600. The cables we included are also arguably better quality as well because they are more flexible.
Many people don't realize increasing power output by 50W in SFX at the current 600W+ level is much more difficult of an engineering exercise than for ATX PSUs. I think in some ways this review article is also at fault for marginalizing SX650-G's 50W power increase over the SF600. Our SX600-G was released in 2014 and SX650-G in 2017, so that means it took three years to make an SFX PSU more powerful by 50W (while making it perform better, quieter, with more connectors, etc...) for around the same price!