They will ONLY work with 2.5!!!
With 2.6 or 2.7 you will have an error message
it's easy to clean(and fixtures will still work). What is not easy it's flickering and random tilt of fixtures after the error. Those units are NOT Illegal and they are well made. But if you're planing to use 2.5 then it's fine but if you need to use 2.6 or 2.7 get a REAL Martin unit.