For Internet access, I use Verizon's cell service. For a couple of years, I used Verizon's dedicated hotspot device, but didn't like carrying along a hotspot and a cell phone. (It was like carrying two cell phones).
Around 2005 or 6, I used to use my first smartphone (an old Palm Treo, I think) as a hotspot using PDAnet software, but Verizon got wise to it. Eventually, the PDAnet access was forwarded to a Verizon page where they offered hotspot access for a fee. Damn, BUSTED!
My last two phones (Motorola Droid Razr Max HD, Samsung Galaxy Note II) have had Verizon's speedy 4G/LTE hotspot feature. Besides the cost, the main downside to having a hotspot feature on your phone is that it uses a lot of battery resources. The two phones I mentioned are well known for having long battery life.