4k video recording not a gimmick - has huge quality improvement
Picked it up from GSMArena. The details are so much better with 4k, even though Note 3's 1080p recording is already the best among the bunch, so 4k recording is definitely not a gimmick like TheVerge tried to imply. (watch it full screen with the video on 1080p, and see the difference in detail - the grass especially)
That being said, I'd rather wait until chips support the VP9 codec to at least cut the storage requirement in half. 4k (well UHD/2160p) needs 4x the storage of 1080p with today's codecs, and at least VP9 will cut that to "only 2x", which is still a pretty good improvement.
But even then, if you really want to do 4k recording, you better choose a phone with at least 64 GB of storage. 32 GB is not going to cut it, especially since the custom OS seem to take several GB's on their own these days, then you want at least a few GB's for apps and photos, and the rest for 4k recording.