Seasonic and Corsair are pretty close for number 1 spot. Then Antec would be number 2 but some of there units are made by seasonic. A couple you didnt mention SilverStone and Enermax are good PSU's too certain models of OCZ are OK. Cooler Master they are junk. The last two Glacial Tech I didnt even know they made PSU I thought they just made heatsinks and Chicony Power I have only seen a few of these and they didn't get all that great reviews.
Delta is the third OEM for Antec. They currently make the Earthwatts line, as well as the signature series.
I laughed a bit at this list. What you listed are brands, but as being pointed out these brands don't make the PSUs themselves. Corsair doesn't make a single PSU. Seasonic and CWT makes them, and then Corsair sells them.
Of the brands you have listed up there, I would take/use Corsair, Seasonic, and Antec. If none of those are available in my price range, I would use a Thermaltake only after I make sure its one of their good ones. Not listed but under the same rule is OCZ. Brands 5-7 I wouldn't touch. Ever.
The ThermalTake XT line is getting good reviews over at JG right now. I know the 775W scored well. ThermalTake like OCZ and other brands have good lines mixed with bad ones. Which is why I said I would use it, but only after looking online for good reviews.
My experience appears to be different. They are not my preferred brand, but im ok with them. Since you mentioned JG, they have never given a Thermaltake a bad review. And thats half a dozen units at least over 3 to 4 years. Not first tier, but respectable overall.
They do tend to overrate and overcharge though. That's their biggest weakness.
Yes, Thermaltake tends to overprice their quality units. The Toughpower 1000w and the Corsair 1000HX are practically the same PSU but the Thermaltake usually costs $40-$50 more. For what? Their inferior customer service? Please.
OCZ has made it easy to not recommend since they appear to have EOL'd all of their high quality units(the ones made by Impervio,CWT and 3Y Power) other than the fairly new(and somewhat overpriced) Z-series Golds.
Thanks to everybody for the posts. I just wanted to know which one is the leader in PSU manufacturing but I understood that almost all of them are made by Seasonic
No not at all. Seasonic doesn't even make most. They make their own AND they OEM for other brands. But there are a lot of PSU makers.
Some like Seasonic and Enermax make all of their own units. Others like Antec and Corsair have others make the units for them. And others like Channel Well and Enhance mostly OEM for others.
Knowing the OEM can be helpfull because some are know for better quality. If your a brand that cares about quality, your more likely to go with a good OEM like Seasonic, Enhance, or Channel Well among others. If quality is less of a concern, than lesser OEM's like Deer or ATNG are in the mix.
But in the final analysis, the end brand is still responsible for the product. They have the final say on the design and 2 units all based on the same design made by the same oem, but from different brands, can vary quite a bit in price and quality by the time they reach market.