Still on Verizon Unlimited Data - Buy unlocked or upgrade to HTC One?

Assuming the HTC One comes very soon on Verizon, it's really the phone I want (not knowing the status of Moto X on vzw).

I'm on month to month, still grandfathered into my old unlimited plan, and finally stopped using my barely functioning Droid Incredible (original, i.e. 2010), and am using my wife's iphone 4, which I can tolerate, but I'm an android/PC person.

Curious to hear some thoughts on if I should spend the extra on buying something unlocked and keeping unlimited, or if Verizon is going to screw me anyway and force me onto a data plan, and it will be for naught.

Need to get off this iphone, and hoping to do it as soon as Moto x or One comes to Verizon.