In general, the WuHu/Bowande models work well. We were running the latest Decapod at my friend's track just last month. All live steamers have quirks, nice features, and some things that make you say "why did they do that"? Among the nice features, WuHu uses a ceramic burner and has a window in the firebox door area so you can see the flame. In the 'why' category is the lack of cylinder drains, so if you overfill the boiler you get hydraulic locking which is a pain to clear.
The Falk, I believe, needs some sorting. If you search the US Mylargescale.com forums you'll find many threads on the subjects. [Google "site:mylargescale.com Falk wuhu".