Does Sprint not have LTE where you're at?
Or - God forbid - is this how their LTE network performs?
For those that were wondering if iPad Air's truly were unlocked, they are. I purchased an iPad Air for Sprint from the Apple store today. I came home and activated it on Sprint's network. They are offering 2 GB's of data for tablets for $15/month. I then went to the T-Mobile store and purchased a Nano Pay as You Go Sim Card for $10 (They made me also buy the 2 GB for $30 for the 1st month). I came home popped out the Sprint Sim Card and swapped the T-Mobile one into it. I turned the iPad to airplane mode, for 3 seconds then switched airplane mode off. It went to searching and after 30 seconds it found the T-mobile network. I did a speed test and got 209 Ping, 22.80 DL/5.31 UL speeds on T-Mobile. On Sprint it got 147 Ping, 2.94 DL/0.30 UL.
Unfortunately Network Vision is supposedly complete where I'm at but as I get within 3 blocks of my home, the signal drops off from 5 bars to 1 on my reception. My phone cycles through 1x-3G-LTE and can't get a good signal. Just recently LTE has been popping up on my phone more frequently, but as you can see through the speedtest T-Mobile blows Sprint away. I have gotten as high as 27.39DL/5.21UL speeds on Sprint so I know in my area so I know it's possible.
So I took the SIM card out of my iPhone 5 and was able to insert it into the iPad Air. I was able to connect to the internet with pretty good LTE speeds. With the iPhone SIM card I got 89-Ping, 7.35-DL/3.84-UL. With the iPad SIM card I got 93-Ping, 7.36-DL/0.89-UL. I did receive a message that the SIM card was locked and I would have to power cycle the device but I was able to continue to surf the web on safari.