Maybe I'm wrong, but I've use both and as far as I can tell, LTE onOff and LTE Switch both do the same thing. They are both a shortcut to bypass using your phone's keypad to dial *#*#4636#*#*/Phone information.
I can't tell that one works any better or faster than the other, so just pick the one with the icon you prefer.
Verizon says to delete all third party switching apps and use the one they now have built into the last update because they cause a conflict, but theirs only gives you the choices of LTE/CDMA and CDMA only. It doesn't give you the option to use LTE mode and LTE mode is the only way I can get and keep a somewhat stable 4G connection when using the TBolt as a hotspot.
Deleting apps that work is not the answer. Verizon needs to fix theirs so that it works as well as the third party apps. Or maybe they tried to simplify it because they think the users are too dumb to figure out how to use it.