No exclusive to a scale here but there are few her into O as a main pasion.
I use Peco for my main HO empire. But I just acquired a pair of O scale locomotives and plan to set up a small layout, little more than a loop of track with branch line and a station or two. I've little experience with O scale and am still researching my options.
Sorry if this was the wrong forum, I've posted a number of HO related questions in here over the years and didn't realize this forum was exclusive to HO and N. I'm not into "toy trains" so it never occurred to me to post over there.
Anyway, if MTH is discontinued, that limits me to Atlas or Lionel. To my eyes, Atlas looks more realistic, but Lionel looks more sturdy.
This forum is almost all HO gauge and N guage modellers. You would probably get more responses on the Classic Toy Trains forum.
In HO, i find that most track manufacturers who use "fast" in their product names are making short sections of sectional track. Atlas HO makes sectional track but also longer pieces of flex track which can, within reason, be shaped to suit.
MTH, by the way, has itself closed so their products will only be available if someone else picks up the lines.
It takes an iron man to play with a toy iron horse.
as asked.