I'm still working on my equipment inventory for the new theater and I'm debating going with HPL 575X vs HPL 750x in my Source4's. I definitely want to use the long life model for budget reasons. I was originally thinking about going with the 750x because it's about the same lumen output as the 575 but 5 times the life (see chart below). HPL 750 300 hrs 21,900 lumens HPL 750x 1,500 hrs 16,400 lumens HPL 575 300 hrs 16,529 lumens HPL 575x 2,000 hrs 12,360 lumens On the other hand, it's a black box with a typical throw of 25-35 feet, so that extra punch isn't REALLY necessary. With 750's you are pushing it a little putting three on a single 2.4k dimmer. With 575's you can comfortably put 4 on a dimmer. 575's are cooler for the HVAC system, easier on gel, and easier on gobos. Now after talking it over with a buddy I'm thinking of just going with the 575x and keeping a dozen standard 750's in stock in case I need some punch for a specific scene. What do you use and why?