if not the V20, then go with samsung........only go with Panasonic if you can get the neo pdp panels available in V,G,S series. U and X series do not have neo pdp, therefore are not recommended. Though being decent entry level tv's you will find better entry level tvs with Samsung.
Remember V series is the top of the line for Panasonic, V20 was rated as one of the best 2D tvs of 2010, if not the best. You cant compare it with entry level tvs from Samsung, no comparison!!!
Suggest to keep trying to source V20 at a good price, only if not possible then go ahead with Samsung.