I had 2 Sb800. great flashes. strong but recycle a little slow if you need speed, but if you get the 5th battery attachment you get as well. hard to find mint condition today. they go for around $250 used. I sold all 4 of my nikon flashes.
just be aware, IF you ever consider buying 622n slaves, they do not work with their slaves as an on camera flash. off camera, yes.
I personally use asian flashes. I beat on mine nonstop and they are workhorses. I use yongnuo 3 560III which IMO would be the perfect if they had hss. I also use 5 shanny SN600N flashes. they have it all for $80 a pop. 1/3 stop less power than the Sb910 recycle faster than the SN910. ittl, manual strobostic, hss. quick locking foot, 14mm-200mm lens spread. build quality is solid also.
565/568 are considered older gen to whats out now. great flashes but the feel and performance has gone a step forward since.
https://www.youtube.com/watch?v=wGwmXwAAcRU
you might also consider looking at the pixel brand or godox, but I dont have experience with them. I was looking into getting the v860 ving flashes but they had a sever problem with their battery pack and it not giving even half the performance they rated. im think theyve fixed it since but after that, I stayed clear. look into them as well before you decide what you need.
neither do the phottix at $300/400 a pop. thats way to much to spend for any aftermarket flash. you can get a whole set of transceivers and a flash for that price. no aftermarket flagship flash needs to cost more than $150 with receiver inside.
godox offers one for $180
GODOX – V860II-N – Nikon TTL Radio Speedlite – Now Available | FLASH HAVOC
Ive used the 860 at a wedding from a friend who just bought it and the ttl was crap. this is the mkII and might be better, dont know. personally I now shoot manual mode solely as ttl is very bad. ive said it before but the cameras have advanced in terms of fps, af speed and accuracy but ttl has not advanced one step since the f5. I use manual mode so I can control what I need. specifically on the dance floor. there are lights all over and the ttl system gets confused. you can shoot 4 images of people standing and get 4 different exposures.
anyways. good luck.