It is an remarkable runner. I posted something about it when I got one sometime back. It is rather plain as to detail - at least next to Legacy and locos costing two to three times as much, but quite well made.
I bought two more I liked it so much, modifying one with more detail and updated sand domes and such to modernize it into the 1940s look, and changing out the tender on another for something smaller. Since buying the first one, one or another of the three of them has always been among the four locos on my layout.
It's gearing makes it run very slow compared to other Williams locos (and most others) and as such, conventionally (all it will run) it is perhaps the smoothest slow runner I have: no better than a Vision Hudson in this regard, but as good - but then V Hud costs about eight times as much.
Note there is a good review/test of it in the latest OGR. Good article.