Judging by the latest rumour it will be very good:
The thing you have to weigh up with any upgrade is will the phone be a significant step up from the previous model to warrant it's price point, the rumoured price on the Note 6 will make it a hefty investment.
I'm as guilty as the next person at wanting the latest tech, i think at some point you have to say to yourself does my current phone do everything i need and does it do it quickly.
The 32GB storage is plenty for what i need, music is mainly what i use the storage for to listen to music, the battery life is more than enough because it easily gets me through a day with quite a bit to spare, the Note 5 is blindingly quick and smooth, it takes great photos, i like Marshmallow so far with the bigger icons.
At the end of the day it's just a phone but it's great to have a phone that you really enjoy using, i'm not sure i've said that about any past phone i've had, i've liked them but each one has had it's quirks like the Note 4 with the speaker on the back which wasn't the greatest idea to position it there, this current phone is as close to what i want from a phone that i've had in my hand so far.
The point i was making really, will the Note 6 really justify a price of £600 - £700 compared to a Note 5 that you can pick up for around £400 now, less if you find one in the classifieds on a tech forum. It would need to be something very special to make it £200 - £300 better than a Note 5, i'd want it to make my breakfast and tea for that kind of money and do the dishes and ironing.