I looked at the Bushnell Inox 400 a year ago--and didn't consider it then because of the map resolution, the costs of downloading satellite images, and the lack of marine charts. I am not sure if the XM NavWeather agreement has been worked out with Bushnell yet or not. There was a recent financila piece which suggested that, but there was also a post on a GPS site saying it didn't work last week. The XM weather is well proven and one of the portables which use it is the Garmin 376 (which has a built in XM weather and XM radio reciever, as well as --at about twice the price. I use a Garmin 176 as a back up--good Garmin maps are available, it works on batteries and on 12 volts, and is a well proven unit.
The I finder H2O C is certainly a good GPS, cheaper than the Bushnell, and the Garmin. The advantage is both the Create a map Topo and the use of Navionics or NautiPath chart chips.
I think that Garmin is the only chart plotter which actually uses the XM weather (the Bushnell is thru the Baron XMC serice--which also powers laptops--and I blieve is used by the military) Most of the other XM weather services are thru computers.
Of course there is Sirius weather: RayMarine, Furuno, Nothstar and PC--but no Lowarance...