That is amazing--so well made!
An extension table like that came with my machine and I stopped using it. Two reasons: my arms would go numb being at such an angle--although sitting on a pillow helped; but the other issue was the quilt kept getting caught on the corners and it would interrupt the flow of the stitches--and I need all the help with flow I can get. So, this past week I quilted eight small projects without it and made out better.
If you figure out how to keep the quilt from catching on the corners--please let me know!!