My Whaler has a FG non-skid deck. Its easy to clean with a mop, but nevertheless it always looks dirty. When we swim off the boat and come back in dripping wet, the deck gets slippery, regardless of the "diamond grip". However, the worst part is that the bow section (not under the bimini) is almost too hot to walk on. We need to throw a towel down.If the boat has a fiberglass diamond grip deck I would not cover it.
Our 19' cockpit was also $1800, and the swim platform was $600. The cockpit is snap in, so if there was ever an issue, any single part could be replaced.As for stains, haven't had one yet. And I fish, no wine on board. Hoses right off and if not, then a mild detergent (boat soap) usually gets the rest off.
$1800 for the whole cockpit? That's a steal. I paid around $500 or so just for my small swim platform.