I noticed that you no longer have the 2 year 200GB OneDrive and Skype offer with the Pro 3, and if we look at the Core i5 256GB 8GB model, it cost 50$ more.
If you are new to the Surface Pro, the Pro 3 is a great choice.
If you have the Pro 2 going to Pro 3 is poor investment, as the CPU is the same as the Pro 2.
The i7 option is a very poor buy, as it is still a dual core CPU, just with HD5000 graphics instead of HD4400, where the performance difference is small, and teh big problem with Intel, which prevents you from playing games at higher settings, is that it does not fully support DirectX and OpenGL, despite Intel claims, which results in numerous crashes with rendering issues. As Intel seams to be a bit more serious and start putting somewhat of an effort in their graphic solution lastly, I would say wait for Broadwell (5th generation Core i). Also, the base clock of the Core i7 is 1.7GHz while the Core i5 is 1.9GHz. While the i7 can go up to 3.3GHz compared to 2.9GHz, this is under Turbo Boost, meaning if the CPU sees that it has the room (thermal wise), to clock at its peek it would. Else it won't reach the peek speed. So only reviews can tell if it can actually deliver 3.3GHz a lot, and not only peeks a few times, but really stops at 3GHz or something.
So to me, the upgrade form Pro 2 to Pro 3, is not worth it, unless you REALLY, but like REALLY need the larger screen resolution or looking for lighter (~1.76lb instead of 2lb).
If you do, remember that the pen, it looks like, Microsoft switch to N-Trig pen technology, so expect to purchase AAAA's batteries to operate the pen. Yes, 4x A's. So finding those are hard, and you have no battery indicator anywhere to know how much you have left. So you need to always carry a second battery with you in your pocket if you use the pen a lot.