Trainmaster, I will give you my honest feedback, if you want it. First of all I think it's great you are involved in the hobby and making videos. I checked out your youtube page. But personally, I'm not going to watch a 20 or 30 minute review of a product. It's just too long.
I would look at reviews of other products to see what works ( It doesn't matter if they are trains. Look at electronics or whatever interests you). You might find it helpful to write a script and storyboard your shots. That way you can think about what you want to say and the best way to get the info across.
For me a 5-7 minute review would be about the limit of my attention span.
