The Sharp XV-Z17000 projector comes with a three year, parts and labor warranty. In addition, the Sharp comes with a 90 day lamp warranty.
Two year warranties are the most common found on 1080p home theater projectors, a few projector models offer three, and a number of lower cost, entry level models offer just one year of warranty on the projector.
Among the 3D competition, the JVC DLA-RS40 (same price, also 3D) has a two year warranty.
Non-3D projectors in the five thousand dollar price range primarily have two or three years: In the US, for example, the new Epson "R" series home theater projectors when they ship will have 3 years (and a replacement program), on their two Pro versions. Their "Home" version of those home theater projectors comes with 2 years, but then it is around $3,000- substantially less. The similarly priced Optoma's have three years, as does the less expensive Mitsubishi HC7000. Sanyo offers three years, on most of their less expensive home theater projectors.
Bottom line, three years, with 90 days on the lamp has to be considered at least very good for a home theater projector in this price range, and it's the longest so far, of any 3D 1080p home theater projector now shipping, that is anywhere near the price of the Z17000 projector.