Confused... 3 different AC1900s

[Rippin6gears]

So I'm a little confused on what model to get.... I see all the ac1900 has 3 different ones as to what would be the best I have no idea.... R6900 R7000 and costco R6900P

 

[pete y testing]

R6900 R7000 and costco R6900P

so looking at those 3 routers there is little between them

R6900 is essentially the Costco version of R7000 and has one less USB port

the 6900p claims to have working mu-mimo

 

[avtella]

I'd go for the non Costco ones, from what I've heard they have less updates. Get the R7000/7000P