I think Motorola got this *almost* right, and with a bit of tweaking, the model could be very compelling.
We've got three of these since mid November, and they've been excellent. They're fast, smooth, have very good battery life (really not looking for a debate on this one - we all average 5 to 6 hours screen-on-time, and about 36 hours before needing a charge - putting it on a wireless charger before bed each night means we never run out of juice). The very light layer of Moto features on top of Android add real utility. Sound and connectivity are great too.
Re: unbreakable screen: this really is a great feature - my wife and daughter would both have had to exercise our insurance plans to replace their phones or screens by now without it, as they've both dropped their DT2's a couple of times. What I think Motorola should have thought through a bit better is the fact that the top removable layer of plastic is still scratchable. It won't break, but if it scratches - which it does far more easily than glass - you'll be stuck with a nasty looking screen until you spring for a new $25 replacement; not a bad price, but with a screen that scratches easily, you may wind up doing this many times.
With this in mind, I added a 0.2mm tempered glass protector (Verizon branded - installed by them at the store for $25 - highly recommended, btw) to each of the 3 phones. Even though the protector is glass, being attached to and "floating" centered on the plastic beneath, it's actually pretty resistant to fractures. My daughter and have have both dropped their DT2's and there are no cracks. My daughter's DT2 is "naked" - no case on it at all. My wife has a simple TPU case on hers (CaseMate Tough on mine).
My reasoning: the tempered glass layer looks and feels great: none of the three phones are showing any scratches at all despite 5 months of heavy use. If you do drop the phone so the glass protector cracks, it's $25 to replace it. But - I think that there will be far less frequent need to replace a glass protective layer than there would be to replace the top plastic Moto "shatter shield" layer. Our phones all look and feel 100% new, and I know that I can keep them like this over the next couple of years, and I will never have to worry about the screen breaking on any of them. THAT is a big plus for me.
I think the shatter proof screen is a wonderful idea - finding a way to market it so that people can have the same experience that my family is having now, with the glass protector on top, would be a bit of a challenge, but can be done - and could be very powerful. The idea that you can have the look and feel of a top of the line premium screen, but repair the worst damage it might incur for $25, is really compelling. I hope R&D in this direction continues - it really makes a lot of sense.