Acer provides a 1 year parts and labor warranty on the H6510 projector. That is typical for under $1000 projectors although there are a few with two years and even three year warranties out there, for those concerned.
An extended warranty, or purchasing your projector with a credit card that offers an extended warranty is worth considering. Figuring prices drop significantly ever two years, with better gear for less, the trick is not to get hit with a repair bill in your first two years. I have an American Express card that adds a year, which would work great for me.
It's your call. Ultimately projectors are pretty darn reliable, especially a 2nd generation model like the H6510, who's hardware is basically the same as last year's H6500 projector.
I don't have much I can comment on regarding Acer support and service, but when Acer launched the H9500BD last year, with some quirky firmware, they came through with a fix in a reasonable timeframe, more than many can claim.
Bottom line on warranty - has a typical 1 year parts and labor - acceptable, but nothing to write home about.