When they say, "molecularly bonding the gold to the metal" that's sales jargon for plating. The whole plating process involves positively charging base metal and then negatively charging gold particles in a solution and allowing the particles to bond to the base metal (stainless steel in this case). Whether its gold "plated", filled or bonded is simply a matter of how long the base metal is able to sit in the solution to allow thicker lawyers of gold to bond. Anything above 5mils of gold is pretty pretty decent and should last a couple of years of regular use. After that, the plating will wear thin and the base metal will show through. Not many jewelers can plate gold and the cost to do it is high--so if you go with a plated watch (or jewelry), spend the extra money to get a heavily plated (bonded) piece. It would be cost-prohibitive to have the piece plated again down the road.
When available, I would suggest opting for a wrapped gold watch. Some rolex reps are sold with wrapped bands and, allegedly, wrapped bezels. (I don't believe the bezels are actually wrapped, but I would like to be wrong on this). Wrapping uses an actual gold foil that is bonded to the base metal with heat and pressure. Several lawyers (wraps) of foils are typically used and the final product, if the process is done properly, should last for years. Again ( and only if it was wrapping was done properly), wrapped gold can be polished.
For most watches, I would probably recommend going for stainless steel. If you're going to go gold, best to keep the gold on the bezel and dial where it won't be subject to a lot of wear and tear. If this is going to be an everyday watch/beater, plated bands/clasps won't hold up long (maybe 12-18 months of daily use before some of the desk dives take their toll). My 2 cents.
