I typically don't get any lag when I do video streaming from my home and work but I have noticed that on occassion it has switched to 3G. Even when in LTE the speed isn't good where it would lag/buffer a lot. I performed speed tests using an app and find it shocking that I'm getting less than 5mbps. My coworker's VZW phone matched the speed as well so there is something going on in the area. Didn't the XLTE get launched? This is very unappealing when I am doing T-Mobile's 7day trial.