Composite Video To VGA (TFT) Monitor Adapter

Hi,

I want to use my PC's TFT display to show composite video as well as use it
with the PC. This would be a switch, not both signals at the same time.
Ideally, the sound would be switched as well. Can anyone recommend a device
to do this? I see that there are a variety of such devices for sale (after a
quick Googling) but would prefere a tried and tested unit/recommendation
from someone who has used this type of device. Will there be any sound sync
problems if I use a cheaper device for example? Do pricier units do the
upscaling better than cheaper ones?

Regards
Tony