It cost effectiveness goes down for heavy data users. Those who use very little if at all will benefit. Also those in rural areas may make it not worth it. I am going to try it out since I rarely use any data outside of work so it can be my personal line to test out. I don't expect much for the price.
I looked at Ting, but after adding in the talk, text, and little bit of data, it was more than Boost ($30), and almost the same cost as my Verizon plan ($50).