I'm using the usual 2.2KW water-cooled spindle on my MDF machine. Yes, it's heavy, and in my particular case way over-powered for what the machine can take, but it's going on the next machine which will be able to make use of the power. The big advantage is the ER20 collet which takes up to 1/2" shank cutters rather than the smaller ER collet on the next size spindle down. And as Clive said, the water-cooled version is relatively quiet and you don't need anything very complicated to set up the water cooling.