Depending on scaling, the lag between finger swipes and taps varies from imperceptible to acceptable. Voice calls sound perfectly normal on both ends, and have about the same lag as a normal cellphone call. During a remote session, the phone's screen remains black. Turning it on will temporarily halt the remote, which presents a button to resume the session. SideSync 3.0 is about as solid a remote control app as we've seen, and is delivered months ahead of similar capabilities from Apple for its iPhone. Its one and only foible that we identified was that it didn't offer a warning before letting us remotely shut off Wi-Fi on the phone, thereby cutting our connection to it.