I should point out that they do a credit check each time to switch... even with a preauthorized credit card to guarantee payment. This is different from many LD phone companies. If you switch back a few times, you will see their names a few times on your credit profile. They didn't warn peope about this on the phone but it's in a fine print somewhere. You accept the whole "fineprints" as soon as you agree to switch.

Think about this if you are getting a mortgage soon. Any inquiry after 3 in a year will lower your credit score so you want to save those for real ones (eg, banks, credit card issuers) Low credit score translates to high interest rate on loans... you may not save after all.