I've seen Arauco once at Home Depot and keep asking for it. I've always been told they've never had it and can't order it.
Then I finally realized that they call it "sanded pine", and even though it has the Arauco name stamped all over it, Home Depot employees don't recognize the name.
Once I finally figured this out and asked about availability, I was told they only get a single order once a year in November. (?!?) Oh well, it's almost November.
I've used 3/8 and 5/8. No complaints with 5/8 but the 3/8 warped terribly and due to the narrow panels I was using it was very difficult to pull back into shape during building. If I use 3/8 again I won't cut it until I'm ready to glue everything together, and do it quickly. Other than that it's lovely stuff, very light, but soft. You can dent it with a fingernail.
If anyone knows of a more consistent supplier in southwestern Ontario, let me know.