In my travels, all I have seen are AC brush motors on hand-held routers. My personal favorite is the Hitachi M12VC. The bearings and brushes have held up to about 300+ hours of use!
I do happen to have a Chinese spindle with a VFD that does not have brushes. They come in a range of powers and are very quiet. I will never buy a handheld router for CNC work again.
http://www.glenspeymillworks.com Techno LC4896 - 2.2Kw Water Cooled Spindle | Moving Table Mill from Omis 3 CMM, 500Lb granite base | Epilog Legend 32 Laser Engraver