I have a Delta bench top mortiser. My mortises never look as good as the ones on TV and in magazines. It is slow and tedious to set up and clamp properly and squarely for each plunge. I just finished cutting a bunch for a project and am thinking that the best thing to do is use a router (with straight pattern bit) after the mortiser to clean up the mortises.
I'm always disappointed to find that home shop tools like my mortiser are designed without thought to clamping surfaces and with poor fences.