All insert heads leave slight "waves"(linear), which only show when held up to the light. Rarely can they even be felt. When used on a joiner for glue joints they have no effect on the quality of the glue surface or the integrity of the joint.
Insert heads will cut with less tear out, because of cutter geometry. They are easier to maintain, because it only takes a few minutes to change knives to a sharp edge and generally last longer because carbide will hold an edge longer than HSS.
Tony