I know of no better warranty than the one Panasonic puts on all of its LB series projectors. The warranty is three years parts and labor. In addition, the PT-LB75U and PT-LB75NTU, (and other LB projectors) have Panasonic's 3 year Zip-It, overnight replacement program. Although Panasonic isn't the only brand to offer a warranty this good, very few others do, (including some Mitsubishi models).
Most manufacturers of portable projectors offer two year warranties, and some only one year. For example, Epson portable projectors have a two year warranty with overnight replacement both years, which I consider to be a very good warranty. Most offer no replacement or loaner warranty. Bottom Line: Both of these Panasonic projectors have the best warranty around!