I used the Tello when I first got it with Samsung S5 & it was fun. Then I got the T1d & it was even more fun. If there was lag, I didn't notice. Now I'm using Tello & T1d with the Wunderphone. Works great. Highest rating on my Fun scale!
I'm running 8.0.0 and get so much lag it's ridiculous when Bluetooth is turned on.