Also seasonic has a small marketing division and budget compared to Corsair, Cooler Master, Thermaltake, Antec, etc.,
That's certainly true, but their marketing is far more effective. One most forums Seasonic is considered the best PSU manufacturer. Many people also believe that there aren't many manufactures. But like I said before there are actually hundreds, Seasonic is only the best known. Why? Because like I said, they have the best marketing.
Marketing is not only advertising, there is a lot more to it. Advertising is only letting people know you exist. If you want people to believe that you're the best, advertising only doesn't help. Things that help for that is for example long warranty. Most people make the connection that longer warranty means higher quality. But there is actually no correlation. The only thing a manufacturer needs to do if you sell a mediocre product with long warranty is selling the product with a higher margin to pay for the higher RMA rate.
Another thing that works very well is, optimize the PSU for reviews. It's not that difficult for a manufacturer to optimize a PSU for the tests done by review site's. You can use sense wires at the end of a 24 pins ATX connector for feedback over the voltage, so that you can have perfect voltage stability with a static load from a load tester. You can use some small capacitors at the end of a PEG, EPS or ATX cable to get the ripple to a 10mV. But all this is for getting a higher rating in a review. In real PC use it won't make any difference as a PC doesn't generate a static load and doesn't care if the ripple is 10mV or like 30mV on the 12V without those caps. These are simple marketing driven optimizations.
But if you actually talk about the best manufacturers, brands like AcBel, Bestec, Chicony, Delta, Etasis, FSP, Flextronics, Great Wall, Huntkey, Lite-On, Murata and Zippy come to mind. Does this means that are always better then other PSU's from other manufacturers? Of course not. It means that they can do everything by them self. From making a design, to actually build the whole PSU and extensive quality control.
If you take a small manufacturer like Seasonic then they are simple not able to do stuff like that. They can not design every PSU by them self, they sometimes buy a design. They can also not manufacturer all their power supplies, they do a lot of out sourcing. Even testing the PSU is something they didn't do a lot with for example the Focus series. That's the reason is was actually known as a series with many problems. Some examples were; high ripple with some graphics cards which let to black screens or freezes. Too tight OCP which would let to unwanted shut downs. Fan with whining/clicking noise because to lose coil windings. Out of spec 12V ripple before shutting down. It's a side issue of carrying more about performance in reviews but les about real life problems.
Does this make Seasonic a bad manufacturer? No it does not. But please don't spam fut, just because you want to defend your brand. There are simple a lot of better brands.
Some more info:
http://www.jonnyguru.com/forums/sho...r-TX850-80-Plus-Bronze-Certified-Power-Supply