The type of lamp is rarely a consideration in choosing a projector however the lamp life almost always is. Note that typical figures are quoted which means the manufacturer has tested the lamp under optimal conditions in order to quote a figure but you may not get this length of life. Most manufacturers warranty the lamp for only 90 days after date of purchase (the exception being NEC with 180 days). This is because there are many factors which can affect the life of a lamp including heat, dust in the air and how often the filters are cleaned.