My favorite spots so far have been the lower back/love handle area, and upper thighs.
Arms weren’t comfy for me, so I use them for Dexcom instead. Stomach is ok for me but I don’t love having stuff there for some reason. I need to start branching out a little though.
I’ll confess I tried the butt pod thing and absolutely hated it, lol. Sorry @T1Allison 
I have never been so happy to remove one!!