well if its within ur budget then samsung series B650 with 100hz will be better in motion resolution compared to the V550A u can notice the difference of 100hz in fast chases in animal planet,to some extent in football basicly if the video content has realy fast moving images .if u want 100hz in sony(its 100hz is better then samsung) the sony W550A is the model to go for,but the price will be quite high for a 46inch.
but the drawback of samsung is its glossy screen,so u will notice glare ,unless the room is dark or as ligthing that doesn't cause glare ,also in general if the tv screen reflects light then there is no use of the extreme black levels the spva panels are capable,u will simply not notice those blacks if the tv reflects light.this were the sony models have the edge they have a NON-glossy screen,even the best of the lcd like the X series still have a NON-glossy screen.