They're quite different. The LT156 is based on LCD technology whereas the LT150 is DLP. The LT156 is somewhat brighter (1200 lumens) vs. the LT150 which is 800 lumens. However, the contrast ratio of the LT156 is only 400:1, whereas the LT150 is 800:1. In a darkened room, at home, you probably won't notice the difference in brightness, but you will notice the difference in contrast. Also - not sure about pricing - but the LT150 is somewhat cheaper - $1700 pricing errors aside!