Got my set last weekend, added 4 30" sections and 27" radius track. Engine runs and sounds great and looks good too. Came from O Scale (too heavy and expensive) and HO (too small for aging eyes).
No issues with smoke (I don't use it - hard enough to breathe), but did notice the light shinning through the observation room. Was intending to paint the inside of the roof black, that is usually enough to stop it.
Found some good articles on adding stream LED lighting to the passenger cars, but wish there was an "interior kit" for seats etc. For the price, the quality of this set is great.
So far, S is really fun.