The decision was a little easier for me when I realized that I don't ever talk on the phone, texting and pictures is most important.Ugh. Can't decide. I also printed out and made cutouts.
As a phone, I would take 4.7 hands down. The 5.5 is larger than my face. But I, and everyone do not just use the iPhone as a phone.
There are a lot of pluses for the 5.5, for me, that I wish I could get in a smaller form. The OIS is great. The resolution is great for screenshots (I use this a lot in my work) to get hi res shots for comps and such. To watch videos (again something I do in work a lot) in larger res is important to me. And of course battery. As well as editing photos and video on the fly on the phone (I don't do a lot of this now but who knows in the future). I deal with images on the day to day. I'm not a gamer but I can see how it would be the right choice for someone that is.
The cons are it's comically large. Hilarious when you hold it up to your face like a phone. I literally giggle holding the cutout. And it seems really big for a pocket, which is where my phone is all day. So I'm not sure I'd like that on the day to day.
The funny part is when I first printed out cutouts, the printer shrank them. meaning the 5.5 cutout ended up being in-between the 4.7 and 5.5. Ironically, it would have been perfect.