just the opposite for me; I was always feeling like I was overpaying for what I got with ATT..Tmobile has been FANTASTIC for my family, and I save a TON of $$$
I'm on ATT with a really high cell standby. Light-ish use, off the charger at 7:30am. Was at 37%, so I'm charging now so it won't die during dinner. Cell standby is 24%. I'd upload a screen shot but I don't see where to do it on the mobile web site