I have both.
Love Forza, I actually play online with people I met at the Nurburgring...
Been playing Forza for a while, I loved the cordless wheel for the 360 - as I can't imagine having a gaming rig in my living room (I am not that committed).
I bought
this to connect the XBOX 360 wheel to the XBOX One, works pretty well with some futzing around.
Gran Turismo is routinely delayed, and I find the PS4 controller not the greatest for me.
+1 for not giving your credit card to Microsquish, they are going to try everything to bang it as much as they can. My bank has a thing called ShopSafe, I love it, you can generate a number good for $X in charges that is only good for Y months where Y > 2 months.
The PS4 is a great machine, I like the fact the HD is easily user changeable, and the interface is a little less cluttered, but no Forza.
B.