1 of 1 people found this helpful
As a former user of the iPhone 6 Plus and now the proud owner of a 128 GB iPhone 7 Plus I would have to say that the upgrade for me was totally worth it. The iPhone 6 Plus that I had did not have the 3D touch capability and I got some pretty sweet new camera features with the iPhone 7 Plus. Upgrading from the 6s Plus however, you may not see much of a difference unless you are an avid user of your phones camera.
As far as the time it takes to upgrade in the store, they are usually pretty quick and iPhone to iPhone upgrades are pretty straight forward when it comes to transferring your data so I don't foresee them taking too long to help you get set up especially if you are already a pro iPhone user
I will say that given Apple's history of releasing new phones, if they keep the way they are going, we may not be long before we see the iPhone 7s or 8 depending on what they choose to name it. If upgrading is not something you need to do right now, it might be worth waiting a bit to see what the next iPhone as to offer.