How are you guys getting 3g/4g

That's pretty much what you're going to see via Verizon.

CDMA: when unthrottled, data tops out at roughly 2.5Mbps down, ~1Mbps up.

LTE : throttled for everyone, to 3Mbps down, 1Mbps up.

 

I've never used an unlocked phone, so I can't really vouch for them. But if you want AT&T LTE service on Straight Talk, they offer the ZTE Unico at Wal-Mart. With this phone, during the late early morning hours (slightly before 5:00 AM EST), two speed tests came back faster than 60Mbps. The fastest of the two was 67Mbps, but during the day when everyone's phone is on, the speeds understandably drop.

At work during the day, I can't get a good signal from AT&T, because the nearest cell tower is one mile away and there's nothing but forest between the two sites, so the signals are minimal. No service or signal issues with Verizon LTE or CDMA with Straight Talk, except the speeds are limited (CDMA limitations) or throttled (LTE).

 

I ordered an LG Access LTE just because it had a bigger screen, ran 4G and was still on their $45 plan. My previous LG 3G phone went through Verizon, but had to be switched to AT&T for the 4G connection, according to the local Walmarters. The switch took about four hours to wake up, it's been wunnerful ever since.

 

Recently got a Straight Talk SIM package for my iPhone 5S after coming off a Verizon contract. I installed the nano SIM from the packet, and now works like a charm. The iPhone 5S is an OEM Verizon model, and since all new Verizon phones come automatically unlocked and with dual GSM/CDMA bands, I had no problems going from Verizon to Straight Talk in matter of minutes. The bar reads "LTE", and I'm getting about 10 MB download speed, which seems faster than what I had on avg with Verizon... & I cut my monthly bill by $17! But
I lost tethering, so there's that, but otherwise...
One question I have is, am I on the AT&T network now with this Straight Talk nano SIM?