Well, the G3 still feels like a phone, it's size is more akin to the s5 and m8 and I can comfortably use it with one hand... The note 4 is actually a fair about bigger and even with my large hands, I would have had to two hand it... So it depends on your expectations.
Completely agree. I'm impressed by what the Note 4 offers, but when I went out and compared the Note 3, S5, One M8 and G3 recently, I found the Note was just uncomfortable for me to use. Reading the specs it doesn't seem like it's that much wider than the G3, but it's just enough wider to put it outside my comfort zone. And while the G3 is wider than the S5, it almost feels smaller in the hand, I guess because of the curved back and very narrow sides. It was the most comfortable of the group for me.
Otherwise, I would wait for the Note 4. It's going to be a beast, with the best display in the business.
In the interests of full disclosure, I have fairly small hands. None of these devices is really a one-handed phone for me, but the Note was uncomfortable even two handed. For someone with larger hands, the Note might feel just fine. I think they all have a one-handed mode that shrinks the entire screen, or certain functions on the screen, too.