I have a Sprint Note 2 and will buy the Note 4 for tri-band LTE. I assume it will have some improvements from the Note 3, but whether the screen size or resolution goes up from the Note 3 really doesn't matter to me. Removable battery and micro SD card are absolute must-have features. I'd rather Samsung stick with light-weight and durable plastic than pander to all the metal-casing fanatics, (who can go get an iPhone or an HTC One if they value a jewel-like exterior over function).
Just remember if you use data and voice at the same you won't be able to on a tri-band phone unless on wifi.