Corsair and Seasonic are probably the best heavy duty PSUs you can buy. They're built to withstand all kinds of abuse, but don't last as long as other PSUs. They have rails that put out more amperage, but not the most efficient PSUs available, though. Not cheap either.
Fortron Supply Group (FSP) and Antec are built for long-term reliability, though they're a bit delicate. They have very stable voltage output, but don't have much in the way of high amperage output. Very efficient and reliable, low chance of DOA. They aren't the cheapest.
Thermaltake and Enermax have decent balances between durability / reliability, and power / efficiency. They're not the best in any area, though they suit the mainstream very well. They are also quite decently priced, but most enthusiasts don't go for these if they have the choice.
With everything else, YMMV.
You're missing most of the equation. It's more who built it than who branded it.
Channel Well Technology
Seasonic Electronics
FSP Group
Enermax
Topower
PC Power & Cooling
There's a few others, but those are the main companies. FSP Group is what I'd call the typical power supply--you get what you pay for in sub-450W units. They're good low-end and mid-range. Seasonic is a wide-range manufacturer. They produce basically the most efficient units, and are known for stability and their former OEM work. Channel Well Tech is basically Seasonic's primary rival in the mid-wattage industry, and they're pretty big doing OEM work for numerous manufacturers. Then there's Enermax and Topower. They typically come out, dominate for a while, but are forgotten. All high-end stuff. And PCP&C is pretty much the big name but usually overlooked, in favor of outside models that don't get stuck with an 80mm fan due to marketing.
There are a bunch of other manufacturers that are typically ignored; Micros Systems, Unitek, Hipro, Acbel, Atng, Power Tech, Compucase, MSI, Sun Pro, Solytech, Wintec, and some other really bad run-for-the-hills stuff.
ANyways--back to the point I'm making.
Seasonic OEMs a lot for Corsair (their HX520/HX620, VX450 and that new 400W model, TX650), Antec (NeoHE models among others), and some other major manufacturers. They make good units--all in the past few years have been 80 PLUS certified, so very efficient. Antec sources from Seasonic and Channel Well primarily. Enchance OEMs for Silverstone and some others, just as Topower does. Everything else non-major is hit or miss, and even the big names have bad runs. I remember about 2 years ago, having the Enermax Galaxy line turn to crude after a few bad lots.
