It's not what AT&T offers for the same price. Before I switched to Tmo two months ago, my wife and I had AT&T. Probably the same 23% corporate discount. 500Mb plan for her, grandfathered unlimited data for me, no text plan (Google Voice or iMessage), 700 minutes/month split between the two of us. Total bill (taxes, etc.): $121/month with discount.
Tmo: unlimited everything (well, 5GB of 4G data) with no discount, $140/month. I'll probably knock that to 2.5GB (we don't use that much) and bring it on par with what we paid on AT&T. Additionally, though not directly related to the comparison, we don't have to say "Mother, may I?" for tethering, so we can knock off another $30/month for iPad data.
Tmo: unlimited everything (well, 5GB of 4G data) with no discount, $140/month. I'll probably knock that to 2.5GB (we don't use that much) and bring it on par with what we paid on AT&T. Additionally, though not directly related to the comparison, we don't have to say "Mother, may I?" for tethering, so we can knock off another $30/month for iPad data.