Makarevich

Question about nzxt E. Review from THG tells that oem is seasonic (focus+). Why nzxt E and seasonic focus+ in different tiers? 

If we're talking about 12V rail, <1% ripple is in ATX specs, of course they meet it lol. In fact, there's quite a lot of PSUs that don't exceed 0.1% ripple. But Seasonic Focus aren't one of them, with Prime being close to 0.1% while for example Corsair RMx is at ~0.06%. Regardless of whether is ripple can be considered a good characteristic to compare PSUs except it's extremely high.

Not going to blame or defend Corsair on that, still waiting for @jonnyGURU answer on that matter. But for 280$ PSU i'd expect it to contain only top quality stuff too but it's probably not an issue to have lower quality caps on modular board.

Taicon isn't a bad capacitor manufacturer, it's a Taiwanese manufacturer and has a good reputation .. it's used in server power supplies made by Delta and other high end products.  They were started with Nichicon's support.
* well, it's Taiwanese company but they moved the factory to China...
I personally wouldn't mind seeing them on a modular board, especially if they're used for additional filtering only.
 
I imagine the Taicon's are listed in the BOM for those power supplies as 2nd source (if they're out of 1st choice for that part, use Taicon as acceptable alternate)
 
 

then hydro g would be a good choice. 550w will do here
 
and i don't mind a tier a psu here, as my personal limit for multirail is at 650w

that is correct, but the nzxt e has been modified, as it needed a dedicated ocp rail for the current monitoring. as nzxt e hasn't shown the ocp tripping issues, it never had to be set higher, so it doesn't have ripple issues either

Translation for you, his complains :
- A LOT of compound on filter caps and chokes (it's a bad thing huh ? that just reduces coil whine i guess).
- One TAICON cap on that vertical board on the side (don't know what's that), MAYBE some TAICON's somewhere under DC-DC (?) transformers (he's not sure and apparently doesn't want to desolder anything lol), and apparently all of caps on modular board are TAICONs also.
- Flux everywhere. I don't see anything on the video honestly, there's like 2 points where it's really visible at most.
Also he has poked it with multi-meter a bit, measured thermals with laser thermometer lol, all that under undisclosed load (if at all). That's it. Typical YT "reviewer".