LCD's do not make SD shit, its all down to the panel of choice the tv contains. For example Samsungs are widely known to have a pretty shit analogue picture where as Toshiba and Panasonic are normally quite good, it is however true that nothing can beat a CRT for analogue displays.
The Samsung slimfits are okay, their biggest annoyance is more down to the way they handle HD than their picture quality.