This is a pretty great device overall. You can definitely feel an improvement over the A405DL when you need to do something heavy like web browsing but I have some complaints about the firmware.
1) Wireless tethering is disabled and you have to use USB tethering which is cumbersome
2) There's a ton of crap from Google preloaded for some reason. I think this is the main reason the battery life is worse than on the A405DL but maybe it's something else
3) The back button has been removed and you have to use the hangup button instead which feels awful.

It's still much better than a smartphone but not quite as good as an unlocked A405DL which was what I really wanted.

Bought this for my wife because she will only use a flip phone and most flip phones will not work on networks in a few months. This phone has 4G HD voice or VOLTE which means it can place voice calls over the 4G data network and will continue to work for years to come. Now the problem ... I inserted my old at&t nano sim card from my wifes previous phone and it would not connect to at&t. I was sure that the "unlocking" hadn't worked and a visit to the local at&t was worse than a waste of time. Finally dialed 611 for at&t support and a helpful lady there had me up and going in 5 minutes. She said the phone was unlocked but needed to be "activated" on at&t's network ?????
Whatever ...... it's working fine now. Like the design, big screen, big keypad, good value.

I have used the T-Mobile 'Pay As You Go' service on a basic ('dumb' ) phone for many, many years.
However, T-Mobile's decision to phase out 2G service has meant that the areas I could get a signal have been shrinking slowly for a long time, and call quality has fallen to an unworkable level for at least the last 6 months. It has become almost impossible to complete a call. Time for a new phone.
Unless you relent and get a 'smart' phone, choices are severely limited. I saw no point in getting a 3G phone, as they will soon be phased out too. That basically left this model as the only T-Mobile compatible ( 4G LTE ) option I could find.
What do you get from supplier eTrade ?
Yes, it's an ATT branded phone, in an opened box. However, it does appear to be brand new, and complete with all the original documents and parts ( battery and charger only ). I presume it was opened merely to unlock it.
What do you need ?
You need the mid sized SIM card to connect the phone to your service.
Does it work with T-Mobile ?
Yes, I bought a new SIM at a T-Mobile store, which you can break off it any of the 3 sizes ( big, medium, micro ) to fit any SIM phone. It connected to the service with no issues.
Can you transfer phone data ?
To transfer all my contacts, the store had a device which required USB connections to both the new and old phones. These I had to buy ( approx. $4 each ). The device connected to the phones, but only my old phone ( which was supplied by T-Mobile ) would transfer any data. The device could not access the new phone. Maybe this is because of the original ATT programming ? All I know is that the contacts would NOT swap from the old phone to the new one.
Result ?
I have a working phone with crystal clear reception almost anywhere, but I'll have to re-enter all my contact info.
Note
T-Mobile no longer offer their own 'Pay As You Go' service. They have franchised it to a third party, who charge a $3 per month connection charge. Calls are charged at 10 cents per minute.

I've seen many reviews saying the phone was locked. Amazon assured me the phone was unlocked, and it was - as advertised. I ported the number from AT&T to Redpocket (a GSMT sim card - using TMobile towers). I had no problem except that it took me approximately three hours. I've switched other phones to Redpocket in the past (from Verizon and AT&T). This one took about the same length of time as the others. Wait time at both AT&T and Redpocket was long, but based on past experience I expected this. The phone is a basic flip phone, as you would expect, but since it is going to be used by a senior who just wants to talk and rarely will even text, it will be fine. The main reason I'm writing this review is to say that the phone was UNLOCKED, no surprises.

Bought for my 12 year old to replace her former smart phone, which it's been decided she's not responsible enough for, but I still want her to have a way of communicating with me when need be.

This is not a smart phone. First and foremost. However I needed to find a phone which would work with a Mint Mobile SIM card, and had 4g service at a minimum. Most of the flip phones out there are only 3g. So this one fit my basic requirements.

Even though it is branded Cricket, the device I received IS unlocked.

Con: the back cover which you need to remove to add the battery, sim, and optional SD card is VERY difficult to remove. I don't plan on swapping out any of that any time soon!

Pros: not at smart phone. It does have I ternet access but you're not going to downloading apps. But you can get to sites like YouTube and many others. Downside: if you're in my boat where you're trying to limit your child's YouTube usage ... This can be a little of both. But hey, if you tell your kid to Google something that is possible.

Has a built in music player and capability for up to a 32 gb SD card. Daughter was happy that she can listen to music.

Kid has to learn T9 texting. That's a learning curve.

Capable of talk and text.

Durable. Without need to buy a protective case.

Bluetooth enabled. So using it with wireless headphones is a possibility.

Wifi capable so if you're trying not to use your data it's an option. Very difficult to turn off the wifi however.

When it's in standby mode the battery lasts FOREVER it seems. I left it over a week without charging since kid wasn't using it for anything else at one point.

Overall. If you're looking to simplify things this is a good pick.