Optoma's warranty is a good but not exceptional one. They offer 2 years parts and labor, but lack the loaner or replacement programs that some others have. They do have a 0 pixel defect policy - this is usally an issue for LCD projectors, but its nice to see that Optoma will back the concept that every pixel work correctly. A extended warranty option may be available to purchase soon.
To give you an idea of what the competition offers for warranties:
Panasonic (PT-AE700u) a popular but less expensive, LCD home theater projector, offers 1 year warranty, with overnight loaner. A extension warranty to expand the parts/labor to three years (but not the loaner), is available for a few hundred more.
BenQ PE7700 projector- 3 years parts/labor, with a first year replacement program (via 2nd day shipping). This is a great warranty, however customers that have experienced a problem with this projector in the first few months of shipping are complaining that BenQ does not have replacement units available on a timely basis.
InFocus Screenplay 7210. Two year warranty. (Same as the Optoma projector) I do not believe there is a loaner or replacement program, but as of this writing, I am not 100% certain.