In addition to all the poly people here who have kids and are doing an awesome job raising them in openly poly households, we also have a few members who were themselves raised in poly households who seem to be perfectly well-adjusted adults.
While I can't offer any personal experience, I can say with certainty that raising children in openly poly households does much more good than hiding it from them. Assuming you're practicing good communication and honesty, those skills and values will inevitably be passed on to your children, and nothing but good can come from that.
And of course, there's the fact that children thrive in loving situations, and the more love they have, the more they thrive. I also believe that children are much more resilient to change than grown-ups are, and we don't give them enough credit. The key is to explain what's going on and let them be heard, rather than making them into passive, powerless observers.
Gralson: my husband (works out of town).
Auto: my girlfriend (lives with her husband Zoffee).
The most dangerous phrase in the English language is "we've always done it this way."