I have used the smooth, shiny goodness of the vitreous enamel grills and hotplates and loved them. I can't remember the brand but just got them from Bunnings, they were about $45 each. I have bought two sets of these (home and holiday house) and both are still going strong, I was even considering taking them off my old bbq and putting them on my new unit but they are not quite the right size.
If you do buy some and have the opportunity to inspect them make sure the hotplates you get dont have any tiny imperfections/pimples that will catch your barbie tools. I remember opening 3 or 4 packs before i was happy.
I have only cooked on SS plates once and found them to be sticky and hard to clean. I would like to try them again though and will probably get some eventually.
re SS burners I considered these but given the price I ruled them out, they won't add anything to your cooking experience and cast iron burners cost about $20 each can last 10 years or more.