What inverter are we talking about? I ordered the factory installed inverter on my B41, it was pricey but a real high-end one. They put in a MasterVolt Combi inverter/charger which is quite a piece of tech. See specs and features here:
http://www.mastervolt.us/marine/products/combis-inverter-charger/
I would say the Beneteau installation is first rate but the wiring and overall installation seem quite complex and probably more so if doing a post delivery installation. A lot of people seem to get by with cheapo power inverters that you can buy in auto store but unless you want to occasionally power A/C equipment, I wouldn't recommend those.