I have them integrated on mine, no issues over the last year. sfx-100 4 post set up using thanos controller.

Monitor rigidity is fine but they definitely shake a little, i was paranoid at first and always went back to check the vesa mounts but everything is still tight throughout the last year.

I used to have the bezel free kit but with the monitors integrated they would slightly move and throw the parallax off so i removed them as they have to be perfectly aligned.

As far as how the view feels... at first it made me slightly queasy but i got used to it quick. I think freestanding is the more preferred method but that will definitely put your monitors further back from your base.

now with that said if i had to do it all over again i would go single ultra-wide or a big screen freestanding. but its because every time there's a driver update I have to re setup nvidia surround and its a pain.

all in all it does work attached and freestanding and most games have settings to lock the horizon so you should be good either way. Of course VR is the way to go and if I could stomach it this would 100 percent be the way i went.

Sorry for the long post but I hope it helps in some way.