All built in HDTV browsers have some sort of limitations, if not a whole slew of them. None yet replace what we enjoy on our computer desktop environment. Given the limited horsepower of 99.9% (arguably, all vs a typical off the shelf PC) of HDTVs, you are better off extending your computer desktop using a simple HDMI cable/wireless keyboard/mouse.
I seriously suggest you re-examine anything you purchase in the consumer electronics area as an 'investment'. There's more utility in buying an HDTV with halfway decent PQ and mating such a beast with a cheap netbook w/ VGA or HDMI output IME.
I want to get a Smart TV with a full-functioning (and quality, if possible) internet browser. I'm looking for a 30-40" TV. But the browser is the key as I want to explore development for TV browsers. It seems as if the Firefox and Opera browsers are not in the marketplace yet.
I understand that there may be better solutions today, but I'm looking at this more of as an investment.
I appreciate your thoughts.