We bought our '06 Cameo with dual pane windows. Weight not a major concern and they do add to insulation and sound deadening. Elimination of condensation on the window glass is a BIG plus.
However, our experience is that they don't age well. Three of our windows have lost the seal between the dual panes. That results in a cloudy build-up between the panes that can't be eliminated without either full replacement or utilizing a specialty repair facility that can cut the seal, clean the inside and reseal prior to reinstallation.
Either way is very expensive per window. Don't think I would go with the dual panes again. Might be OK if you trade up every 4 or 5 years but if you plan to keep your RV for 10 years or so, these things will come back to bite you down the road.