Not always. I have 5 lines, 4 of which are iPhones. Only one person uses less than 2gb's a month. That being the case, I'd need to use the 20 gb plan at least as everyone else uses over 4 gb's a month. It would run me over $300 dollars. ($200 for mobile share plan, $30x4 for the iPhones I have and then $30 more for the basic phone on my plan) That's $350 before taxes, right? My 15% Fan discount would take the share plan down to $170 for $320 before taxes, right?
Currently I'm on the 700 minute plan for $60 for the first line, $9.99 for the remaining 4 lines... I get unlimited text and free mobile to mobile calling for $30, I pay $30 per 2 lines for unlimited iPhone data, $25 for 1 line of 2gb data, $50 dollars for 5gb data with personal hotspot and nothing for the basic "dumb phone" for a total of $264.66.
Fan discount of 15% on main line, every single data plan and every single line charge drops bill down by $39.70 for a total of $224.96 before tax.
Just wanted to break it down that depending on usage needs, the share plans aren't always the way to go. Unless you want to give money away.