AT&T packages are not much different than Verizon. Certainly not 60% better. In fact, every time AT&T initiates a price drop, Verizon matches it.
Sprint prices are lower, but coverage is lower, too. Sprint SHOULD be 60% better because they have 60% LESS COVERAGE! For some, Sprint is a viable option. Just make sure you will have coverage where you NEED it. I have had Sprint, they did not have the coverage I required, I left. What good is paying LESS if you can't use your phone. I keep an eye out on ALL major providers each time I make a phone purchase. If another provider will give me the coverage I want at a lower price, I will certainly go with them.
If another provider gives me coverage which doesn't meet my needs at a lower price, that does ABSOLUTELY NOTHING for me.
Keep in mind, "bundle packages" aren't just price. "Price" and "coverage" are ALSO a bundle.