Does Apple make different iPhones for T-Mobile and ATT?

Question

Here is the question, Will a T-Mobile phone have fewer dropped calls than an ATT phone under similar conditions, Both iPhones each having a T-Mobile simm card in each? The ATT iphone was a 4s and the proposed T-Mobile iPhone 6 plus.
Here is our story, In May 2014 , we moved to the metro Denver/Boulder area we arrived with iPhones 4.S purchased from ATT but had switched service to T-Mobile before our move. The cell phone service was unsatisfactory with a number of dropped calls. so we switched to iPhone 5s from Verizon .
Now we are interested in buying a iPhone 6 plus each for me and my wife so we are considering a T-Mobile iPhone 6 plus because of their deals however, I am suspicious of their service.
Today I went to the T-Mobile store and relayed our experience with the ATT phones/T-Mobile simm cards. They assured me that the problem was with the ATT phones and not with T-Mobiles service.
1.Is this accurate?
2.Would you stick with Verizon?

Answer 1

swifty8 wrote:
1.Is this accurate?
No, it's utter nonsense.
AT&T and Verizon tend to be more expensive than Sprint or TMobile. Sometimes, you get what you pay for.