I'm going to wait for the family shared data plans and LTE iPhone to roll out before I decide.
My iPhone is Unlimited, the second line on my acct. is the 200MB (or whatever it is) and the third is 2GB.
I'm torn on how I want to proceed, since they up the throttling limit to 5GB on LTE for unlimited plans there's no motivation to go tiered unless they offer a $30/mo 5GB LTE plan.
From there, if they have the right offering for the family shared data it could be enticing. I would love to buy 5-6GBs for all lines to share if that would also allow for tethering on any of those lines...
this is exactly what I was about to post....unless they offer 5gb for $30....stay with unlimited.