It really depends on what the customer wants. I started refinishing Corian last year because the "authorized Installers" who are supposed to offer refinishing will quote nearly 75% of the cost to replace it. That's when they whip out the samples and photos of their new stuff that looks like real granite or marble. I learned how to use some incredibly durable, breathable, and long lived abrasive pads on a machine that oscillates and rotates while vacuuming up the dust dry. It's the same system I use to hone and polish stone (travertine & marble). I do it dry so I can see jsut where I am in the process. When you do it wet between grits you have to stop, pick up the slurry, squeegee the surface blow or wipe it dry so you can see if you cut out the marks from the last grit. That takes too long. Done dry you know exactly where you are and where you need to go till you change media to the next grit. Simple, sweet and efficient!
Corian is much like doing stone only harder because the resin loads your media so quickly. I've taken out nicks, gouges and scratches as well as changed the sheen to whatever the customer wants. I was surprised how differently people appreciate the sheen of their corian.