496 = good stuff
While I personally prefer not to mount handheld gps devices in the panel because of obsolescence, I also think the 496 has some advantages over the Aera series that make it a fine choice. Here are two that come to mind:
1) Tactile buttons. Users familiar with the x96 buttonology can usually access most information without looking at the unit. You can't do this with the Aera. Touch screens are cool, but they have no tactile feel, forcing you to stare at the device while you poke at it. Not ideal in the cockpit.
2) Auto mode. If you ever use the 496 on road trips (I know it's crazy to drive when you have an RV), you'll find it has some great display options. You can display aviation information and weather on the road map. I don't know of any other aviation handheld that can do this. The Wx overlay is great for winter driving.
I think it's too bad that the 496 is being discontinued, but I'm glad I have one. Given its quality, I'm sure I'll get another 5 - 10 years of reliable service out of it. Having the latest stuff is cool for a while, but I certainly wouldn't be ashamed to have a 496 in the panel of a shiny new RV12.