Don,
FWIW here's the product manual for the the 300 watt inverter I'm using. Notice on page 45 under "PROTECTIONS" that it has reverse polarity protection (an easily replaceable common automotive fuse) on it's DC input side - IMHO a very important feature for an appliance that might get attached many times to a battery during it's lifetime:
http://www.samlexamerica.com/documents/manuals/11001-PST-300-12-24-1215_Web.pdfI don't know about a "nice big fat transformer" being necessary or not nowadays, but my little Samlex is many years old and has been really knocked around a lot. I just use it on various 12V receptacles in the RV and it has performed brilliantly so far.
P.S. For some reason, that 350 watt inverter in your link doesn't appear to be a regular/current Victron product:
https://www.victronenergy.com/inverters
