As a kid I spent a lot of time with HO trains and gradually built a huge layout in my parent's garage. Fast-forward 25 years later that HO layout is still there and my Dad and I still run it every few months (these days over a few beers) ...So in general, I would say that I have a fairly good perspective on various HO related train stuff. My son who is currently only 3 is really interested in trains and I wanted him to be able to begin to enjoy the model train experiences that I did as a child, but I felt that he was not quite ready for the complexity of the huge layout that I built as a kid. So...I figured I would give this set a shot for him to play (**supervised**) with. To start with, I have set it up as a simple circle/oval and as my son grows into it I will add the various accessories, piers, bridge, etc.
Now for the actual review...
As one of the other reviewers mentioned, this set is WAY better than what started with as a kid! The quick-connect track is perfect for running on carpet (or whatever other surface really) No little metal spade connectors to deal with, and both the physical and electrical connections are solid. In addition, I was really surprised at how well the cars and locomotive are detailed...definitely on par with the more expensive brands that were available 25 years ago when I was into this. The supplied transformer is a little chinsy, but it still works fine. The locomotive is very smooth in both forward and reverse. All the cars roll well, and provided you take the care to assemble the track correctly the train seems to work equally well in both forward and reverse with no derailment issues (provided you do run it a reasonable speed). The extra accessories are a really nice touch...not necessarily super-detailed nor perfectly realistic, but they still add a fun touch for the kids to look at and play/interact with.
The key thing to remember with this set (and HO scale trains in general) is that, this is not really a toy...it is a scale model. If your expectation is that you will give this to your five year old to play with...you will be very disappointed as the thing will probably be broken in a day. Trains of this size require some patience, dexterity, and fine motor skills to assemble and put on the track, and these are traits that most kids probably don't have until 7 years old or so. In addition, trains of this size tend to be somewhat fragile with their various small features and should be handled with reasonable care. However, if this is for an older individual, or you are purchasing this with the intent that you will interact with your kids while playing with this together, I think you be very happy.
I would rate this set five stars if the supplied transformer was just a little bit better.