I did almost the same thing with a Droid Razr Maxx yesterday becoming a S5 as Verizon had a major sale that is running through the 27th I believe. Same three phones(essentially) and I chose the S5, it came down to the G3 and S5 for me and I've seen enough people who have early hand's on the G3 having battery/overheating issues so I went Samsung for this cycle. I don't think either of us will regret this, samsung seems to be the biggest fish at the moment.
I also ended up with two Iphone 5s's in the order for the family that I can't convince to switch so I still feel dirty over the whole thing - But I was able to pull off the buddy upgrade to keep my unlimited data plan for one more cycle so I'm psyched about that.
Anyone have any good tips on setting up the S5 with foxfi or hotspot program? My bet is that day is coming to a close very quickly...
If the S5 is anything like the S3 you can root it, install Cyanogen Mod and tether to your hearts content.
Do you have any more details on the G3 battery issue? I am 95% sure that's the phone for me.