Pioneer's HDTVs are considered by many critics including HomeTheaterReview.com, to be the best looking on the market especially their KURO line. Kuro is the Japanese word for black and Pioneer's plasma HDTVs were known to have the best black levels in the business. Pioneer's sets were often more expensive and less energy efficient than LCD sets from the likes of Samsung and Sony. Pioneer's sets also often came at a premium price which in these troubled economic times sent customers looking for an HDTV towards other lesser brands.
Pioneer's exit from the market will likely help the rise of LCD HDTVs in the market place over plasmas as Pioneer was a true leader in the plasma market.
Pioneer makes many other successful and profitable electronics products such as Blu-ray players, AV receivers and many other components. With players like Vizio in the market, the profit margins and price points for plasma HDTVs have dwindled down to the single digits.
Source: Twice.com, CNET.com