I was going that route with HE. for whatever reason the first few devices i tried to add (sylvanis br30 bulbs) wouldnt pair, no matter what i tried. i had a 2nd smartthings hub i bought on a whim (im around 310 devices, so was moving some off of the first hub to SOMETHING else), and they paired in no time at all with the ST v3 hub. for now i think most of the new devices will go to the ST v3 hub. it still seems to be really fast (sensor on v2 turns light on v3 hub on REALLY quickly), and its what i know and am comfortable with. i would still like to get more stuff moved to HE (i still use it with harmony and fully kiosk controller, which is awesome), but for the time being im going to be mostly ST, just spread across 2 hubs. im going to move a bunch of virtual devices over to see if that helps any. once i get my new switches installed (on the v3) and my old switches installed in the new house, ill see how it all performs, then might move some hardware to the new hub if its struggling with performance.