For what it's worth, I was very hesitant about the M8 at first because of the non-removable battery. However, based on my previous post, I decided that I could make it work.
Since then, I am very glad I went with the M8 (if you couldn't tell), but do sometimes envy those who are now using wireless charging docs in my work area. I kinda wish I could use one too because they are very cool and convenient. But the more I think about it, the more I realize that the wireless changing would be the only thing I really would like about the GS5 over the M8.
Tough decisions are always best with a few days sleep... LOL
Also, depending on your carrier, most allow you to return a device within a certain time frame (plus a restocking fee) if you do not like it. Verizon is 14 days and, iirc, a $35 restocking fee.
Kratos