I'm a Note 4 owner. I've been happy with my Note 4 aside from the lagginess of touchwiz (which is minor). I went through a stage of disbelief when the specs were revealed for the Note 5, but I've decided to buy the phone anyway!
The battery and the SD card are not my top concerns, I'm doing just fine with 32GB Note 4 so 64GB Note 5 should be quite nice for me... my point is - they did upgrade the specs in the storage department, base model isn't 16 laughable gigs anymore, it's 32.
What bothered me the most was the IR blaster. I cannot understand why they would remove such a thing. I'm not going to be able to get over its absence, but I'll figure something out for my IR needs.
I'm also a little annoyed at the use of glass for the back. When a phone is in my pocket, the screen faces my flesh and the back faces away from my body. When I bump my leg on the corner of a table, a glass back breaks. I already know the future for my poor Note 5, it will have a broken back and its resale value will be destroyed. I might try a dbrand or a case this time around (usually go fully nude), we'll see how slippery it is.
so why did I decide to upgrade? I'm just insane I supose. I love the Note's s-pen, I think Samsung Pay looks absolutely killer if it works as advertised and demonstrated. I could quite possibly not need to carry a wallet anymore. admittedly I might need a case that can hold my driver's license and maybe an emergency debit card/cash. Maybe I could keep my license in my glove box in my car. Maybe time to buy those door locks that you can operate with your phone. I seriously am probably a bit too excited for Samsung Pay.
Why else did I upgrade? Foolishly optimistic about hardware and software improvements. 4GB RAM sounds great, octo-core cpu sounds great, updated software should have even less lag than the Note 4 (we'll see, still haven't seen anyone press the recents button on a Note 5 ... that's my benchmark for comparison)
Also, fuck Samsung for not giving us stereo speakers on the Note - I use headphones so I guess I don't care, but geeze.