Not visible to naked eye, unless you are a videophile of the highest order.
Nikema, no idea to your second question. Re: Vizio, yes, I have one. Really good quality. For the price I paid for it, can't beat the deal. HD channels look amazing on it. Bought it 12 months ago for $650 (42" LCD), with 2 HDMI and all the other connectivity options you may need. No memory card slot though, but that was not a factor in my decision. It has a RGB/VGA slot, so I can plug my laptop to it and watch picture slide shows as well as all kinds of YouTube videos and cricket streaming. Can't ask for more for that kind of money.
I think theres a difference, as I first got a 720 sharp, and then returned it to get a 1080... Also, the PS3 and its blue ray player was a big factor for me paying extra for the 1080. One thing no one mentioned was response time, If you're a gamer, you wont like it if the response time is more than 8ms, esp if youre playing games like guitar hero.
another tip, theres no point in paying $100 for those 'supposedly superior' HDMI cables they sell at BB or CC.
“gold connectors” at the end, and all 