Last year at Christmas we pulled my Dad's childhood O-gauge setup down from the basement. It's 40s/50s stuff and needed work before it could run, but run it does! The old transformer is very deco-cool and the big steam locomotive is just the shiznit.
My Dad has since gotten into it a bit more, "for the grandkids". He had a nice big setup for my sister's kids, with a reversing loop, x-overs, the whole nine yards. He's hoping they'll design their own layout this year (8 and 6).
This year for Christmas I got him some cool rolling stock - a barrel car and a log car, both of which jettison cargo. I can see where this would be addictive!
Provided you have a loco with multiple pickups for the track power they generally run pretty trouble free. The only problems we have are the turnouts; sometimes they make a dud that needs some work. Anything made in the last 10 years should run great, including steam (which was never the case before then). I have one of these made by Bachmann that honestly runs better than some of my diesels:
What turned me away from N scale to some degree was the cost (no cheaper than any other scale in spite of it's size; $10-$15 for a freight car, $100 for a loco) and that I was doing shows with my club. Love my club, but part of the joy of showing my stuff is people noticing it. With N, only the hardcore nuts will notice a custom painted unit. The general populace will glance at it, but move on. The details are simply too small to hold their interest.
(not mine) Here's a rail speeder I built from a resin kit powered by a trolley truck (my first resin kit):
