I'm actually thinking about it- for a couple of reasons. The Galaxy S5 is effectively waterproof, I have seen people in videos strike it with a 16oz hammer and the hammer bounced off (myiPhone got nuked when somebody dropped it off a museum display case I was installing) and the big one for me DUSTPROOF. The lint, sawdust, gypsum, metal shavings, and other crap that finds its way into my pockets wreaks havoc with the charger port and on/off button on the iPhone, I am getting it fixed every 3-4 months. I have got to putting a bit of electrical tape over the charger port when I'm doing something like drywall. That, IMO, is BS.
I have both and as mentioned above they both have their merits. I lean toward the Galaxy S5 because as also mnetioned above, it is water/dust proof and can take a beating. I am very rough on my phones (and don't like cases) and have broken multiple iPhones at work. Still on my original S5... sides and back are beat to all hell, but screen still looks great and no dust under the screen which my iPhones seems to get within a few months. The iPhone excels in simplicity and migrating seamlessly to a new iPhone. I can do more with my Galaxy which is good and bad (malware/hacking), just need to be cautious.
Anyhow, wonder how many people Samsung will get to switch with this whole trail period thing. And what do they do with all those used phones that get returned... I'd take a slightly used 6 Edge for a nice discount!