Recently picked up this engine for my son's 5th birthday, since the #844 is his favorite engine (he loves the steam episode from the Extreme Trains series). The protosound 3.0 sounds amazing, and even though we are running it conventionally with a separate whistle and bell switch the sound system helps to create an amazing experience. I printed out a whistle signal guide and the kids have been practicing. They also really like the station sounds.
I know many of us obsess over details and realism, but it's also nice to sit back and watch kids enjoy the essence of railroading. This engine is delivering that in spades, runs very smoothly and negotiates small curves well. Despite being semi-scale, the detail is great for the price point and overall is visually impressive.