Our imaging facility houses a range of different confocal microscopes from major vendors such as Olympus, Zeiss and Nikon.  All of these systems, including one purchased last year, were supplied with either a mercury arc burner or metal halide light source, used for observation of samples by eye prior to imaging using the confocal laser scanning system.  These light sources suffer many shortcomings, such as the requirement to frequently replace expensive components (burners, light guides), the need for heating/cooling cycles when turning on and off, safety issues regarding risk of explosion and problems with the disposal of mercury-containing bulbs.  For these reasons we decided to replace all of our confocal epi-illuminators with the CoolLED pE-300white.  Users now have the benefit of immediate on/off with no requirement for warm-up/cool-down cycles, they can fine-tune the intensity of illumination to match their labelling, there is no risk of explosion and there are no problems with the disposal of mercury-containing components.  We have found the CoolLED pE-300white to be highly reliable, simple to operate and work very well with all the standard fluorophores we use including DAPI, Alexa fluor 488, Alexa fluor 568.  To my knowledge there have been no instances where the LED light source has been judged inferior to the illuminator it replaced, with most users appreciating the benefits.  As a facility, the decision to replace our epi-illuminators with LEDs was seen as an investment that should be recovered within three years, with the projected lifetime of the LED illuminators considerably exceeding this time.