The paper presents the features of the Lambda Physik 248 LEX KrF DUV-Lithography laser for spectral performance, reliability, and system integration. The 248 LEX is based on Lambda Physik's series of `LAMBDA' industrial lasers. Data of 5 years field experience with the LAMBDA high power industrial lasers are used to discuss reliability of the laser in and economic aspects of the laser application in terms of cost-of-ownership. Results of an endurance test program for lithography lasers are used to given an outlook on system performance and component lifetime. Based on these data the cost-of-ownership is projected for the coming years and multiple system installations. An update of Lambda Physiks' R&D effort and recent progress is given.