I had great service with sprint for almost 2 years, got bad after the first year and it got fixed later on, and bad again like one month and a half, used to get 1-2mbps download which works great for me but the past month was 0.15-0.39mbps which is useless for videos and sometimes I even had problems with pandora at the gym , decided to go with AT&T , which has way better service where I live and the 3GB seems to be enough , I had a problem the first day of the month because somehow it show the I have used like 800mb but now is fine ( they did give me a credit for $10 for the usage tho)
This is my speeds test on AT&T now
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You also have a month before you decided to stay with them so you should see how your usage is then