I upgraded with the Garmin 345 transponder and the Aera 660. The 660 with AirGizmo dock fits in the same space as does the 396/496.
I now have ADS-B in and out and I like it fairly well. Would I like the 696/796 better? Sure. My only complaint is these old eyes would like a bigger display. But, like I said, the 660 fits the same space as a 396/496.
I also fly with an iFly 740 suction cupped on the right side of my panel. I have steam gages on that side and the 740 fits nicely without blocking them.
There are many choices out there with more coming all the time. Life was easier in Henry Fords day. You could have your new ride in any color you desired - as long as it was black!
Have fun and let us know what you do.