I know that the Gateway 42" is generally regarded as one of the poorest plasmas. Not sure about the 46" - I think this is similiar to the Vizio P4 46" based plasma. The 46" glass for all of the 46" models is made by one manufacturer, but the electronics vary from company to company.
As always, I recommend the
www.avsforum.com plasma forum for a large userbase of plasma owners to ask. I did find one thread despite their search function being down right now:
http://www.avsforum.com/avs-vb/showt...hreadid=346478
I think you would be better off with the Panny 50" or even the Pioneer 43" or 50" rather that getting the Gateway model. The Gateway 42" has a lot of negative opinions...