I am looking to buy some rolling stock for my layout and I am wondering which manufacturer(s) I should look towards.
Are these cars going to be highly used with many people handling them? If so I do not recommend the top of the line highly detailed cars. All those nice detail parts get broken off by inconsiderate or clumsy people operating with them. This for this use the the Athearn blue box kits are wonderful. There is also Accurail, Roundhouse, and Atlas Trainman.
On the other hand is you layout going to be a photographed show case? If so then you probably want the highly detailed cars like Intermountain and Kadee.
Then there is everything in between too like the Proto 2000, Walthers, normal Atlas, Branchline. Of course cost is usually an issue. If you need to fill a yard with 100 cars the Athearn blue box at $5 do so much easier than a Kadee at $30 a car.
The only things you want to avoid are things like Mehano, IHC, Industrial, standard Bachmann, standard Lifelike, etc.
On a side note, metal wheels vs plastic wheels. Is there a huge difference,
Yes, there is a huge difference in the amount of noise the metal wheels produce, the number of short circuits they cause, and now well they roll.
Our club switched to metal wheels in order to keep the track cleaner. HA! They didn't help at all in that regard, so now there is a big movement to switch back to the plastic. The noise issue is probably not nearly as big a deal on a smaller layout, but at the club with 10 trains going simultaniously it is a dull roar. As for how well they roll we have found that most locomotives have so much power compared to the trains we pull it is a moot point (our biggest siding will only do a 20 car train). On the other hand if you need the same locomotive to pull 45 cars instead of 30, metal wheels might be the way to go.