I personally would be a little nervous about a machine that can run of 110 or 220. In my experience with welding and plasma cutters, 110 isn't even worth fooling with. It simply does not get hot enough to do anything, even 16ga is a struggle.
The 40A on 220 should be good for most light metal, I've used a similar sized unit to cut thru 3/8" steel and it was not a problem. I'm not familiar with that brand but if they have a good warrenty you can give them a try.
Have you tried searching for a fabricator's forum? There are a number of them out there. I don't frequent them but a friend of mine does, he's a much better fabricator then I am.