As others have said, I don't think you can find a better value in O gauge than RailKing anything, Scale, Imperial or other. Also as others have said, many pieces of rolling stock are difficult to tell whether they are scale size or not unless you have a Premier and RailKing car of the same type to compare.
I mix them all on my layout, but I am now leaning more towards more scale size items. I also have some operating cars for my grandson and I to play with for just plain old fun. I am not that prototypically motivated and sometimes we just put a bunch of stuff together and run it, no matter if it's scale or RK sized.
I think layout size is also a consideration. If you have a layout with smaller curves, then RailKing anything is the way to go. Although not scale, they even have the big steamers that will run on O-31 curves. Folks can have items on a smaller layout with all the looks and detail of the larger scale items and at a much lower cost as well.
I have only diesels, but if I were ever to have any steamers on my layout the RailKing steamers are much more in line with my budget than the Premier ones are. I think they are roughly about half the price of the Premier steamers and look just as good, just a little smaller. My track is all O-54 & O-63 so they fit in well with my layout too. Not sure what it would look like with a RK steamer pulling Premier rolling stock though? May not be that bad looking either?
