What company to go with considering my situation.

I'm currently on a post paid plan with T-mobile.. Looking to cut my cell phone bill down. I also mention I'm a OTR truck driver so my internet usage is very high since I'm rarely connected to wifi. I've been looking into visible (have a friend that recommends them) but he's connected to wifi most of the time.. How I will use my service is going to be significantly different than how he uses his. What company has the best coverage for unlimited data.. I don't want to get throttled after I hit 50gb as what I see with visible.