Heat is just while the phone is downloading updates and syncing for the first time. Mine went away completely after a few hours and now it's running cool and smooth as a champ! LOVING the S7 edge...enormous improvement in smoothness and battery life from my S6 edge.
Yes same here, when restoring my stuff from my Note 4 it go hot but nothing since. every now and then a bit lag here and there when scrolling but that's about it. Not sure I will ever try a water test lol. I have the At&t Gold S7 Edge. too early to talk about that battery, need to let it cycle a few times then but for right now it drains kinda fast. Again, too early on that.