The Note 3 is a great phone but for me the Note 4 is still worth the upgrade.
The camera is much improved on the Note 4, as is the screen.
Battery life is also better, as is performance.
I also prefer the new design and feel of the phone.
We're probably getting to a point now where improvements are only going to be incremental. However, the note 4 improves on the Note 3 in almost every area, and to me it's worth the jump.
While it's a given that from year to year, OEM's will increase hardware specifications to make the "new" series of phone "better," I don't think that the jump from the Note 3 to the Note 4 is quite as significant a bump as it was from the Note 2 to the Note 3. Speaking specifically to what the US providers offered, I've broken down the most significant improvements:
Note 2 to Note 3
- Quad-core 1.6 GHz Exynos 4412 vs. Quad 2.3ghz Snapdragon 800
- 16gb vs. 32gb internal storage
- 2gb RAM vs. 3gb RAM
- 720p vs. 1080p
- 8mp rear camera vs. 13mp rear camera
- 1080p video capture vs. 4k video capture
- Physical dimensions Note 2 151.1 x 80.5 x 9.4 mm (5.95 x 3.17 x 0.37 in) vs. Note 3 151.2 x 79.2 x 8.3 mm (5.95 x 3.12 x 0.33 in)
Note 3 to Note 4
- 1080p vs. 2k
- quad snapdragon 800 2.3ghz vs. quad snapdragon 805 2.7ghz
- 13mp rear camera vs. 16mp rear camera
- 2mp ff camera vs. 3.7mp ff camera
- 3200mah vs. 3220mah battery
- Aluminum trim vs. Plastic
- Physical dimensions Note 3 151.2 x 79.2 x 8.3 mm (5.95 x 3.12 x 0.33 in) vs. 153.5 x 78.6 x 8.5 mm (6.04 x 3.09 x 0.33 in)
Now, like I mentioned, stating whether or not a phone is a "true" upgrade, is all subjective. But, just looking at the jumps from the Note 2 to the Note 3, to me, those were far significant improvements as compared to what they did with the Note 3 to Note 4. That said, I still think the Note 4 is a great choice for phone, but I still take the viewpoint that, if I were upgrading from a Note 2, it would be a no brainer. Upgrading from a Note 3 all comes down to what is most important for people's needs.
The Note 4's upgrades didn't have enough larger jumps for me, to warrant an upgrade. The most significant choices for me, would have come from the amount of internal storage, the RAM, and if they had increased the screen size without compromising the physical dimensions. I had stated previously that, the taller height of the Note 4 felt somewhat awkward to me (although, I probably would've made an adjustment easily), but again, that's all subjective as some people prefer that.