Is it optimal get a Verizon iPhone 6, even if I plan to use T-Mobile currently?

I really am not sure of the answer to your question because LTE service is not important to me. I live in Costa Rica where the local carrier uses GSM but LTE is not widely available yet. I use my Verizon iPhone 5S while in Costa Rica after swapping out SIM cards and it works just fine. I am under contract with Verizon, hence my use of that network when I am in the USA. One thing of interest though is that this website claims the T-Mobile unlocked/contract free iPhone 6/6 Plus works with a Verizon SIM card. That's news to me as I thought that particular device was the GSM model without a CDMA radio. If it does actually work on the Verizon network and you are not contract bound, it seems you might want to purchase the T-Mobile iPhone.

Maybe not. And this website may explain how this is possible.

"The situation is much better this year as the new iPhone 6/6 Plus features new VoLTE (Voice over LTE) technology, which means you can buy a GSM version and still can use a full range of services on CDMA networks. For example, you can buy a sim-free T-Mobile phone and completely avoid CDMA to use it on Verizon."

Yes, I originally got my iPhone 6 from t mobile when I got fed up, I had them unlock it, borrowed a friends verizon iPhone 5 to start a prepaid account, then put the sim in my six, and it's been running like a champ on verizon. Full EVDO Rev a and b, and fast LTE, and my phone has been working much better and receiving more signal in more places then on T Mobile.

So glad to see a recent reply. My question is the same as the original kirkegrd post. I have spent hours on the phone and in TMobile and Verizon stores trying to get a straight answer and the only thing I am sure of is that both carriers want you to buy "their" Apple phone and will tell you whatever it takes to get the sale. I need help. I am 65 and technology does not come easily to me. I want to upgrade to an Apple 6 and an Apple 5c from two iphone 4's. I am currently at Verizon. From what I have read online, it appears that I could upgrade at Verizon then take my own device to T Mobile in future should I choose. Doing so would enable me to return to Verizon with the same devices should I be unhappy(er) at T Mobile. Various online sites say that this can be done (Verizon to TMobile) but not the other way. If Apple is building the phones to do either, is TMobile installing something to prevent it after they unlock it? I understand TMobile will not unlock until after 40 days of service but OK. The TMobile store told me today that there are different "versions" of the Iphone and that one purchased at Verizon would 99% probably not get all the features if taken to TMobile even though Apple builds the phone able to do GSM or CDMA. Said I should buy from Apple direct if I might go back and forth. Is this true? I have a large credit at Verizon so would like to purchase there. They said their experience was this was the case with many phones from other carriers including Apple. I understand the conflict with phones created specifically for a CDMA or GSM network but I can't figure out how to sort the truth from the baloney on Apple phones. Any guidance appreciated on whom to believe.

It isn't a technical issue.

Verizon does not accept carry in phones that are not already in their system and the GSM side of their iPhones is unlocked due to an agreement with the FCC or acquisition of airwaves. So it you are contemplating returning to Verizon but you want to try T-Mobile then buy your iPhone from Verizon (make sure you pay full price and avoid a contract) and then you can return to Verizon if you wish.

Thank you. And do you know if all the TMobile features will work if the iphone was purchased at Verizon? The TMobile store says no I won't be able to get 4G LTE or WiFi calling.

They could be correct regarding LTE bands, they are correct regarding WiFi calling.

And so it must be something Verizon does to the phone when they activate it that prevents it from working on the LTE bands from TMobile? I sure wish I understood more of this. It is a lot of money to spend on a phone that locks you into one carrier until you have another $700 to try a different service. Thank you for your assistence, I have preferred Apple for a long time but at this price you had better love your carrier.

The Verizon iPhone 6 and 6 Plus should work on the T-Mobile LTE network in the US. Other models do not support the necessary LTE bands across the Verizon and T-Mobile networks.

Use this reference chart to help figure out which phone you should be buying.

http://www.apple.com/iphone/LTE/