To me one of the most interesting topics involve tracks to be used for layouts whether permanent or temporary (around the Christmas tree). From my own very long experience, I started out with 027 when I received my first complete set in 1950 and for a number of years afterwards this is what I used for our Christmas layouts. For my first permanent layout when I was 14 or 15 I graduated to 0 gauge tubular including 072 for an 8' by 12' layout. I remember my father building the permanent plywood table. It was ingenious on his part because it kept a teenager home and a number of my friends would congregate at our house for an unofficial train club. We realized the tubular tracks were not that realistic but were easy to assemble.
After college, military service, a career and marriage buying our first house I move all the boxes of trains and continued with 0 gauge in an attic layout. Unfortunately my children never got into the model trains. Decades later and a new house with trains packed away for at least 25 years I started again with a 9' by 12' setup and continued to used tubular 0 gauge. My wife got me a complete set that came with fasttrack that certainly looked better than the tubular and as I began to replace it I noticed that the fasttrack was often harder to join. Not so long ago I had purchased the Lionel Christmas Mickey Mouse set for my 4 year old grand daughter. She could not piece together the fast track it came with but when I substituted the old tubular 0 gauge she actually could join them.
I decided to abandon fasttrack for my permanent layout and I stumbled on to a "fire sale" of K-Line's supersnap which was not only more realistic but came in long lengths at a reasonable price that fit together quite well. I was even able to purchase 0-Line switch tracks to replace my old 022 Lionel and my layout is now all supersnap. Unfortunately the availability for supersnap appears to be drying up. I never looked at Lionel's Super 0, Atlas, or Gargreaves and I would be interested to hear experiences of others in terms of tracks they use, have used and how/why they changed.