I don't know, Gear fit looks like a dumbed down version of the Gear 2 to me.
Step by step comparison to the review, just for fun (and only things I think are worth mentioning).
Gear 2 has a rectangular display. It just makes sense unless you are looking for a Star Trek prop.
There is no light sensor either but when you have the watch in fitness mode it does keep it plenty bright enough for daylight.
It also turns brightness off automatically after 5 minutes if you max it out to daytime viewing.
I find that pressing the home button once for turning on the display has no noticeable delay and I have double press set to open the camera at the moment. I wonder if it is something specifically to do with S-Voice (which I also turned off on my S5).
I don't particularly like browsing the apps on the gear2. I have to many of them on there

I have put my most commonly used apps to the left and right of the clock though and that helps greatly.
The Gear 2 gives you a warning at 15% (gives you about 8 to 12 hours in normal usage) then again at 5%.
Personal advice, Don't buy the bottom of the range, get the 2 or in a pinch the neo.