So far so great. Probably just as awesome as my moto g3 which averaged about 6-6.5 hrs SOT, although I haven't ran my g4+ down to 10 percent or anything like that-i did a couple times on the g3 though...
so far for the g4+ my SOT when the battery is down to 50% is around 3.5 hrs, which was what my moto g3 usually had at that point when I'd check.
Keep in mind my habits are mostly using irc and opening links in my browser and YouTube. Often with Google Play Music or YouTube Music app running in the background. I don't regularly take photos or videos or anything and I have WiFi location scanning turned off along with the GPS (unless driving using maps)
That said, there's a day here and there that (on both of my motos) the battery drains at a faster rate for whatever reason I'm not sure of, but generally the battery life is solid.