I think the only difference between the 296 and 396 is the inclusion of pay as you go XM service (programming & weather). The nice part is the weather overlay on your GPS map enroute and I think that is about it.
I use the 296 and think it is much more than the typical 150/152 pilot will ever need.
It seems to me that any 496 could only include some form of XM traffic collision avoidance. It would probably need to be a feed from a satellite as opposed to nearby transponder recognition and interpretation, which would require precise placement and be free from any interference.
There must be a point where there is so much visual information on your GPS screen that it becomes confusing and distracting. Garmin is clever and will probably announce a winner, but we will see.
