The issue where the sound of the headphones is slightly behind the image on the TV or audio from the speakers could be caused by the latency of the headphones (the time it takes to transmit sound via a wireless signal) or it could be the device that the headphones are connected into and how that device is outputting the audio signal that is the issue.
Latency occurs in all wireless headphones however the technology being used to create the wireless signal does affect how much latency is caused. For example a Radio Frequency (RF) model (like the RS 120) has a latency of approximately 1 m/s whereas a KLEER digital model (like the RS 160/RS 170/RS 180) has a latency of approximately 45 m/s. Usually the delay (even at the 45 m/s level) is not discernible and hence goes unnoticed.
The component that the headphones are connected to will also affect this issue and could make the inherent latency more obvious. For example if a TV outputs sound to it's own speakers slightly faster than it outputs sound to the audio output jacks that the headphones are connected to then that would mean that there is a delay in the audio getting to the headphones on top of the latency of the headphones so the difference between audio and image would be more obvious.
To overcome latency issues sometimes the component that the headphones are connected into will have a latency adjustment which can be used to adjust the component to match up with the headphones. If the component does not have a latency adjustment then a second option would be to connect the headphones directly to the audio source (ie: cable box, DVD player, etc) so that the headphones get the audio signal slightly before the TV and hence the latency factor compensates for getting the audio signal before the TV.