None, really. Even against the newer phones I've seen so far, I'd still rather have my Note 4.
The combination of a Wacom stylus and MicroSD / removable battery is pretty much unbeatable, ESPECIALLY for folks like me who use their phone as their primary computing device outside of the office/home. I work with a lot of spreadsheets in my business, and I have yet to find a better phone to work with them than the Note 4.
The Note 5 could have been an incredible device, but I think Samsung lost touch with what made that phone special ... it was a great BUSINESS-centric device. But they got so lusty over the iPhone that they tried to out-Apple Apple, which is a losing strategy to begin with, but also in doing so have alienated a lot of their core fanbase.
With prices approaching what I could get a new Macbook Air for, I just can't see what the strategy was for this device ... it's LESS functional than the Note 4 in many ways that matter to power users, and so for right now, the best strategy is to keep the phone you have, or get one at the now reduced prices if you don't yet have the Note 4.