Hi @cz_dave I use the G5 and a Samsung galaxy s5. The CGM in the cloud and xDrip G5 facebook groups are really useful for advice (I'm very new to my G5, only had it on for 15 days).
I use xDrip+ rather than the official Dexcom app as you can get about 100 more days or so from the transmitter, rather than the 120 Dexcom say it will last for. Also, I don't need to restart my sensor/transmitter every 7 days, I've had mine on continuously for 15days so far. Been quite reliable so far though I expect it will get less so in the next week.
I've been running with Dexcom G5 using xDrip+ on an Android phone for a good six months or so as part of my OpenAPS set-up. It works very well and has never had any issues from my perspective.