I used a $5 Woodcraft 1/2" shank 1/4" x 3/4" bit to cut the holes for my sub. The flush trim bit and roundover bits were ... you guessed it. $5 Woodcraft bits. The quality is great, but I only buy them when they are on sale for $5.I ordered up some MLCS bits today... I got the Katana bits where available.
Man made composites such as MDF and particle board have resin bond glue that is wicked bad for HSS bits and blades. Even micro grain/solid carbide bits dull quicker with MDF than with hardwoods.I've never routed on MDF. Does it really chew up the bits?