Seems to me that even if Sprint remains committed to the LTE rollout and stays financial viable while doing it, they will need at last two years to deploy a network with even reasonable coverage. That is a WAG, but it is one based on the slow progress to date of tower updates noted on s4gru.
Even the few cities that are supposedly LTE have only a small fraction of their towers upgraded...and apparently not enough bandwidth or back-haul in place to handle the load even if you are in the radius of one of those lucky towers.
I can't imagine how long it will be before you can drive around with a Sprint LTE device and have continuous LTE coverage....and even when we get there, what will the download speeds look like? They are overselling bandwidth now.
Thus, I see no reason to be with them in the next two years. At the end of that time, one can always come back and reevaluate. If they have a robust network then with decent download speed, are still inexpensive, and are still offering unlimited data, then I will consider coming back...but I am not paying 90% of what VZ charges for data that eeks in at 1995 modem speeds and for a voice network on which I can often not get a connection. My vacation this summer was the final straw. None of the three Sprint phones in my family could place calls reliably in a pretty large area near the shore. I am not talking about a rural area...and we traveled many miles and had this issue, yet a family friend who had VZ was not only placing calls wherever we went, but could also stream video while sitting on the beach.
Unlimited data means squat at these speeds. It's like being at an all-you-can eat buffet where the plates are the size of postage stamps...and the buffet table is a two-mile walk from the table where you eat.
Regarding VZ prices...
Had we upgraded our last two off-contract phones on Sprint, we would have been paying another $20 a month for the "whatever" fee. That would have brought my monthly bill to $197 for a three-line family plan with insurance on all three handsets...with a corporate discount. I have those three lines on VZ now...with insurance...on an 8GB plan with unlimited voice and text...and my bill will be approximately $225 with corporate discount after taxes. About 10% more for data that screams. I'll monitor data usage and adjust up and down as needed. 8GB a month is more than we used on Sprint, but who knows what we will use when data is actually served at useful speeds.