Sounds like they're pretty good lamps. Don't know if they're worth twice as mauch as regular lamps though.
C/P

All SolarMax lamps are manufactured in Germany by an ISO certified factory with over 40 years experience in HPS and MH lamp technology, ensuring high quality and optimized performance. SOLARMAX grow lamps are designed with the grower in mind.
Reduced lamp sizes fit most horticultural lighting fixtures
Custom tailored spectral distributions
Highest output
All SolarMax lamps carry a full ONE YEAR WARRANTY
FLOWERING
As plants approach maturity they require less "Blue Light" and depend more upon radiation from the "Red" portion of the spectrum between 610 nm - 720 nm. The SolarMax HPS lamps have been engineered to constantly deliver 10% more targeted "Red Light" energy to the maturing plant to promote aggressive flowering.