I avoid the store like the plague. The only time I will visit a store is for a warranty replacement, other than that it's a painful experience for me. The store staff is usually friendly but most of them don't have a clue about anything technical let alone what is going on with the network. VOLTE is the only viable solution for Simultaneous voice and data as I don't see them going back to separate radios like you have with the note 3. As far as VOLTE goes, it's a ways out for sure. I would guess at least a couple of years. The Sprint LTE network has it's fair share of issues and signal quality is horrible compare to evdo (3G network). Sprint will have to figure out it's signal problems first before even considering switching to VOLTE which would allow talk & data.

I'm on wi-fi a lot so it doesn't bother me too much but this is certainly a deal breaker for some. So to answer your question, yes I would switch carriers if you need it. You can always come back later but this could be years down the road. As stupid as those verizon commercials are, Verizon has a far far superior network so yes better matters.

Another plus all your modern Verizon phones will support Simultaneous voice and data right now as long as you are in a 4G coverage area which with them is pretty much everywhere unlike Sprint which falls back to 3G in more spots than I can count. T-Mobile & AT&T this wouldn't be a problem with either. If I were to switch, my first pick would be big red simply for the better network, then T-Mobile and last AT&T at least in my market.