I have been imaging using the new CoolLED PE-4000 system on our epi-fluorescence microscope. This is an excellent system as it covers a very wide spectrum of wavelengths. I have found it very easy to use. The user interface is much better as the different LEDs can be changed using the handheld control- without switching off and unscrewing the LAMs as had to be done on the old PE-2 system. In addition the LEDs can be changed dynamically while the software to capture the image is open, and also a huge combination of different wavelengths can be used at the same time.I have found that the light source from this system is considerably stronger than from the previous system - I now image at 50% strength, when I used to image at 100%.I anticipate using this imaging system a lot more now that the new LED light source is there.