At this particular point in time, I honestly do not expect a price difference to be a major factor in staying with Sony or going back to MS. After the MS debacle of selling less power for significantly more money when this generation kicked off, I really doubt either company jacks up the price with either VR or other pack ins. And with the publicly released details, I'm guessing both consoles are similarly priced.
Now, if one company offers significantly more processing power, storage, or other tangible performance features, all for less, the same, or only a little more money than the other company's cost, that would be a huge factor at launch. And would probably sway me.