works great on our motorola razr and our s3.
i buy highspeed internet which is about average 1.5 down .500 up
and i connect to it via wifi and i dont have any hickups.
on ocassion if i call someone on skype(voip) it has issues, it seems to have issues calling other voip services,prolly the other end's bandwith.
but for the most part its solid.
if your inet is fast, then it must be your phone.
back it up reset it and install the app again
the faster the inet you have the better.