I bought a four long straights last month and found the gauge of the metal on the ties was thinner than those of the O-36 curves bought a few years ago,after the launch era issues happened (which cleared up). The big issue was the isolator pads for the center rail let some shorts happen. Some loose pin and ties complaints, but rare.
I paid under $20 and had it on a whim in under an hour. (leftovers go upstairs seasonally, you can go up & look year round) Ordering, I had a 036-circle in hand in under 48hrs by cheapest delivery option (7pm order)
The new ties (long track) are still the traditional shape, but metal gauge was equal to say, O-27 ties; lighter than traditional O. (rails remain thick and about as robust as traditional O)
E.g..... You could step on the thick tie stuff by either brand, stand on it if you aren't a heavyweight that is 😁... and it's possible the long track is the only one with light gauge ties and curves/short straights are still heavy gauge ties.
Step on thin tie M track weighing 135 pounds and your O height becomes close to 0-27 height fast (convenient for me as I used O-27 switches and homespun transition rails from 2" of 027. (I have a small grade going vs shiming 0-27 turnouts to O height)... my dog weighs 135 and got a.spot a little but the rails flexed and didn't bend. The tie just hung until I bent it sides back down.....just like 0-27 except 0-27 rails would bend too. 
(Still thicker than Marx tie metal too)
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