The 2008 rig we had before this one had the Hehr frameless windows that were not dual pane. They sweat something awful . . . water would run down the insides of the windows on days when the outside temps dipped pretty low and the inside was warm and cozy. So when we ordered our new rig (same brand and model), we specified the dual pane windows.
As disappointed as I am in the seal issues with the dual pane windows, I still want them. It's so nice not to have the sweaty windows. I guess if you camp in areas where the temps don't change that much, then this isn't an issue . . . but it was for us.
It's frustrating that the window manufacturers aren't held accountable for better quality. If 3rd party companies can fix the problem with "whatever" technique, the orig manufacturer should be able to use the same technique to improve their manufacturing process.
Just my 2 cents worth.