In my opinion a properly made surfboard has a glosscoat. "Sanded Finish" boards are actually unfinished. A sanded finish is the sanded hotcoat taken down with wet and dry fine grit sandpaper, sometimes with a variety of acrylic sprays to help hide blemishes.
I've gotten pretty good over the years at making sanded finish boards look like sanded glosses. It's been hard work but 90% of the time when you lay two boards that I've finished next to each other you can't tell which one is glossed and which is not.
If the hot-coater does a cherry job cheater coating the laps I can get a sanded finish board nice and smooth without showing any weave of the cloth.
Sanded finishes became popular in the eighties when people wanted to emulate pro surfers. Shops would skip the gloss process to save money and time. Afterall, pro boards were prototypes. No need to completely cherry them out. But more and more people wanted similar boards thinking the pros had some secret advantage. The truth is, no shaper wants to pay for two extra steps in the process(paying the glosser AND wetsander AND extra cost for resin and sandpaper).
You do save some ounces in weight, but honestly you can rarely feel the difference in the water. I've found that the majority of surfers believe that gloss-coats are "thick", adding tons of weight*. When most people think of gloss coats they think of polished longboards. Polishing the glosscoat gives the resin the illusion of depth. Personally I think it looks cool, but I assure you that the resin isn't any thicker wether your board is polished or not.
Gloss coats are brushed on thin with strained resin. I then cut this coat down in half with 220 grit sandpaper, smooth that out with 320 and then block it wet with 400. What's left is a thin waterproof seal. It's important to waterproof your surfboard.
All my personal boards are glossed from my 5'11"s to my 10' footers. I keep my boards on average of 4-5 years before selling them.
*My Channel Islands 6'2' Flyer II is glossed, my old roomates was sanded only. When we traded out in the lineup the boards did not feel different weight wise. I believe that when it comes to surfboard weight the most important thing is that it feels nice and balanced. You don't want the board to have a dead weight, it should feel lively. You want a nice balanced board to get over the ledge and down the line, make it through barrel sections, etc.
