Wait a little longer for that review
My mini-goban from Yellow Mountain Imports arrived today (rather fast shipment) but it has a diagonal warp. Two opposite corners point upwards so it rocks no matter which side I play on. With the 13x13 side facing up, the board will spin on a smooth surface. I tried fixing it with felt pads and later with silicone pads but the warping is too pronounced.
I sent YMI an email to see what they can do. They have a good reputation of doing right by their customers.
The finish on the mini-goban is a few shades lighter than that of the full-sized table goban that I acquired from them back in December. Its color is more towards the yellow spectrum rather than cinammon. It's not an issue for me although I was hoping that the two might perfectly color-coordinate.