I USED to be a big MTH buyer - that is ALL I bought. Railking Only for years.
I'm a steam guy. PS3 ushered in the wireless drawbar in Railking (not a fan but I can tolerate it) and the "lock up stopping problem" in conventional (can't tolerate that at all). Now, I refuse to buy MTH PS3 steam. I've bought a few older PS2 steam engines since, all NIB/Old Stock or very lightly used. I have 2 PS3 engines on order, both diesels - the CP Holiday Train Railking engine and another 44 ton switcher.
Lionel is making what I want. I've been buying more scale stuff just because it is being made and I want it. Lionel is also getting a TON of my money in scale steam locomotives. Again, they run well and they make what I want. I am no fan of the current MTH products - steam especially. As I do not run smoke in diesels, the problem with the "lock up stopping" is non-existent.
I still have plenty of RK stuff - or at least 0-27 sized stuff that I run all the time.
My layout was designed to run Railking sized equipment. It will still run all of the scale items I have. As I will be moving this year, I do not plan to modify the layout to accommodate the Lionel Legacy scale Polar Express set I have on order. That will live in the box. I have 0-27, 0-31 and 0-42 curves. I am also buying lots of Postwar to run alongside the modern stuff.
See video below taken this past weekend. You'll see the Williams Baldwin with Railking cars, an MTH Premier light Mikado (bought through the forum via York - almost no miles on it and runs like a dream). Postwar BUDD cars and Freight also running.