Good questions, I'm in the same boat, but will wait for the 6S. Our 4S gets the boot, though.
I can't decide whether to get the iPhone 6 or not.
Right now, I'm using the 5S 16GB. It's a great phone, feels perfect in the hand, offers all the performance I need. However, I have longed for a larger screen iPhone for a long time. Also, as apps are continuously growing in size and I take more pictures than ever due to the great camera, 16GB is getting cramped. I find myself having to delete apps and photos A LOT.
That said, I was pretty much set on getting the 6 in a larger storage configuration. Rumors suggested that 32GB would be the new standard size. Now Apple made a dick-move to keep the 16GB while completely removing 32GB. I would have much preferred if Apple made 32GB the baseline, or if they would have made it cheaper to upgrade from 16 to 32.
I guess you can't have the cake and eat it.
So, the iPhone 6 would get a bit more pricey than I had hoped. But, I'm fine with paying plenty of money as long as I get the best phone out there. However, I do feel that Apple has taken plenty of shortcuts with the new iPhone 6, some of which include:
* Protruding camera
* Disgusting antenna bands
* Large bezels all around the phone, making the 4.7" iPhone nearly as large as the 5.1" GS5.
* Not much improved battery life
* No sapphire screen
* No Full-HD display in the iPhone 6
* UI which doesn't really utilize the larger screen of the iPhone 6
What are the odds that Apple will correct some of these points, come the iPhone 6S?
Right now, I can't make my mind up.