Month-to-month 4G, from Walmart

  Last week I wrote a piece asking for recommendations on fully prepaid month-to-month 4G service.
  A week later, I think I have the best deal.
  1. $30 per month prepaid T-Mobile unlimited data, voice and text.
  2. $99 no-contract mifi hotspot designed to work with T-Mobile.
  Both are from, of all places, Walmart.
  Not sure if I'm going to sign up, because I can't find any reviews of actual bandwidth people are getting. Hopefully readers will have some experience to offer.