I bought the pink Hello Kitty version for my then 5 year old daughter four years ago. It sounds pretty decent. I really should replace the tuners though.
I asked Empress about switching between tempo and preset mode. This is their answer:
"You don't have to cycle the power. You just have to change the "delay time" switch from "tap tempo" to "slow" or "fast". In "slow" or "fast", you can use presets. In tap tempo mode, you can't."
I have an Adam mounted under my Nano. It fits great and doesn't touch the ground. You have to remove the rubber feet of the Adam and make sure the mounting screws are fastened tightly though.