For range, it was the easy thing of looking at the difference between the before and after neighbour lists. When I had the non-Plus devices, it was four hops to the garage door sensors, and many of the other further away units. Now the only devices that are three hops away are those door sensors (which is about the best it’ll get), and everything else is one or two hops away.
In terms of speed, I’m basing that off of speed of response (which is noticeably faster now).