This new version of the Sony HS-51 is the first Sony home theater projector I have had a chance to review. Since I never got to work with the older HS50 or HS51, I cannot advise on how much it may be improved over them. According to Sony, the HS51A started shipping in the US, this past December.
Here's the basic info on the Sony HS51A:
Technology: 3 LCD panels
Native Resolution: WXGA 1280x720
Brightness: 1200 lumens
Zoom Lens ratio: 1.55:1
Lens shift: Vertical and Horizontal
Lamp life (full power) 2000 hours
Warranty: 2 years
This Sony projector sits in in an unusual price point for an LCD based home theater projector. With online prices around $3000 or less, it is dramatically more expensive than the popular Sanyo Z4 or Panasonic AE900u, both of which are now less than $2000 online after rebates. As a result, its most direct competition does not come from other LCD projectors: Epson's Pro Cinema 800 is significantly more, and the high power Sanyo PLV80, thousands more. Instead, the closest competition, price wise, is from DLP projectors, notably, Optoma's (Hot Product Award winning) H78DC3, which sports the Darkchip3 DLP, and the less expensive Darkchip2 Mitsubishi HC3000 (which I haven't had a chance to review).