Over a year ago I switched to smartphones on share everything plan and the service was FANTASTIC!!!!! However, the data service has been getting slower and slower, with frequent drops down to 1x or no service in many areas in NJ. I commute 50 miles 1 way from Easton PA to western NJ and work in Morris county NJ. Over the last few months service thorough Warren County and into Morris county has become Marginal at best, Thought it may be the Samsung S3, but I use a company provided IPad with the same results. First time in 20 years I'm thinking about switching providers at the end of my contract.
As more people start using 4G and as each user also uses more 4G then of course data connections are going to slow down. Mobile data is not magic.Think of it like the water coming into your house. If you're the only one there and taking a shower it's a nice strong flow. If the dishwasher is going, the washing machine is going, someone is flushing the toilet and yard is being watered, then guess what not so much.