While comparing AT&T, T-MOBILE, VERIZON and SPRINT some of the biggest cell phone service providing companies, it was discovered that all of them have some advantages and disadvantages. We found that SPRINT has the best coverage in the Chicago area, but SPRINT also is the most expensive as compared to other service providers. AT&T, which I use right now, is almost identical to VERIZON. These two companies have a very close competition. However, AT&T is winning right now because of the deal they have with Apple regarding their product, the iPhone. The iPhone is very popular with the customers, and because there are new people buying iPhone everyday, new customers are constantly coming to AT&T for cell phone services. However, the coverage both companies offer is not as excellent as SPRINT, although it is still good, moreover, the rates of both are quite high too. T-MOBILE has average coverage and their rates are not too high either. it does not cost a lot, but the coverage is not very excellent either.