My only significant complaint is the supercap is apparently undersized and any loss of power drops it out in about a second. When you kill track power, it can't complete the shutdown sequence, it does it for a second or so and then just quits.
It's a pulling fool, I pulled 18 Menard's coal hoppers with mine and it didn't have any problem on level track. Note that the Menard's hoppers have a configuration like many post-war cars with more rolling friction than modern needle-point axles, so pulling 18 of them is impressive. It was also pulling the caboose. 
The sounds are great and a lot louder than I would have expected from the tiny speaker.
