My wife has a smartphone and I only have a basic phone with 700 minutes, unlimited text, and 2GB data for her. After doing the math, I found that changing to the share everything plan would end up costing us about an extra $10/month compared to what we have now.

If I were to upgrade to a smartphone and move to a 4GB share everything plan, it would save us around $10 a month compared to the old plans with 2 invidual 2GB data plans.

IMO, the share everything plans are a good deal if you have multiple smartphones and/or tablets you want to put on the plan. Other than that, I'd stick with their normal plans.