Does anyone have first or second hand knowledge of Outback inverters?
They seem to be the only company that makes a totally sealed unit but
have I've never heard of them before, and know nothing of their track
record.

Next question: Outback, Xantrex and others offer the option to sync
up two 110 volt inverters to provide 220 volts. Assuming both
inverters are connected to the same battery bank, my concern is what
happens in charge mode. If both inverters are charging the same
battery bank at the same time, are they able to work in coordination
with each other, or would one tend to shut the other down?